bharsar students - home...many off-farm jobs. it also provides ample opportunities for sustaining...

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PrefaceIndian topography and agro climates are well suited for horticultural crops, which are considered

ideal for achieving sustainability of smallholdings, increasing employment, improving environment,providing an enormous export potential and above all achieving nutritional security. Furthermore,horticulture has the potential for improvement of wastelands as well as arid and semi-arid areas. Thecountry has recorded significant growth rate in horticultural output among various agricultural productsin the recent past. The horticulture sector contributes around 31 % of the GDP from about 14% of thearea and 38% of the total exports of agricultural commodities. Moreover, globally India ranks secondin the production of fruit and vegetables next to China.

Increasing horticultural production contributes to commercialization of the rural economy and createsmany off-farm jobs. It also provides ample opportunities for sustaining large number of agro-industries,which generate substantial employment opportunities. Demand for horticultural produce is rising, bothin domestic and international markets. Many consumers today purchase a broad range of relativelyexpensive commodities such as off-season produce, exotic fruits and vegetables, and organic produce.Demand for horticultural produce is expected to rise further, fueled both by affluent urban consumers indeveloping countries and consumers in developed countries. In addition, increasing urbanization andthe needs of growing cities to feed their population will require more attention toward horticulturalproduction. The foundation course on "Basic Horticulture-I" for class XI students has been introducedwith the following objectives:

This is a basic course to equip students with knowledge and skills in the field of Horticulture.Major topics covered in this book are introduction to horticulture, importance of horticulturein human diet and national economy, principles of horticulture crop production technology,principle and methods of plant propagation, essential plant nutrients, their deficiency symptomsand toxicities, organic and inorganic manures and fertilizers and their methods of application,water management, weed, major pest and diseases management, harvesting, handling, storageof horticultural crops and traits and quality standards of horticultural products etc.

Students will get an exposure to vocational/professional course on the production of fruits,vegetables and flowers, which will motivate students to come up as entrepreneurs in the areaof nursery raising or commercial horticulture.

This course is an effort to sensitize student in the field of horticulture. The course will be usefuland serve as guiding force for the students to choose career in the area of horticulture and theymay further pursue diploma/ degree in this area.

This course has been designed to provide entry level job skills to the students and will help tomeet the human resource requirement for horticulture sector.

Vineet Joshi, IASChairman, CBSE

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Advisors

1. Dr. S. Ayyappan, Secretary, DARE and Director General (ICAR),Krishi Bhavan, New Delhi, 110001

2. Sh. Vineet Joshi, IAS, Chairman, CBSE, Delhi

Special Acknowledgement

1. Dr. Rameshawar Singh, Project Director (DKMA), Directorate ofKnowledge Management in Agriculture, Krishi AnushandhanBhavan, Pusa, New Delhi

2. Dr. Jagdeep Saxena, Editor, ICAR, New Delhi

Authors

1. Dr. Suresh Kumar Upadhyay, Professor, Deptt. Of Horticulture,CSKHPKV, Palampur-176 062

2. Dr. R.R. Sharma, Senior Scientist, Division of Fruits & Hort.Technology, IARI, New Delhi-110012

3. Dr. Manish Srivastav, Senior Scientist, Division of Fruits & Hort.Technology, IARI, New Delhi-110012

4. Dr. Hare Krishna, Senior Scientist, CIAH, Beechwal, Bikaner(Rajasthan)

Editing & Coordination

1. Dr. Biswajit Saha, Associate Professor &Programme Officer, (Voc.Education) CBSE, Delhi

2. Mr. Dharampal Singh, Former Director (EDUSAT & VocationalEducation), and Consultant (Agriculture), CBSE, Delhi

3. Ms. Pragya Gaur, Consultant, (Science), CBSE, Delhi

Acknowledgements

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Convener & EditorDr. S.K. Upadhyay

Authors :Dr. S. K. UPADHYAY

Dr. R.R. SHARMADr. HARE KRISHNA

Dr. MANISH SRIVASTAV

Basic Horticulture - IClass XI

vii

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viii

THE CONSTITUTION OF INDIAPREAMBLE

WE, THE PEOPLE OF INDIA, having solemnly resolved to constitute India into a 1[SOVEREIGN SOCIALISTSECULAR DEMOCRATIC REPUBLIC] and to secure to all its citizens:

JUSTICE, social, economic and political;

LIBERTY of thought, expression, belief, faith and worship;

EQUALITY of status and of opportunity; and to promote among them all

FRATERNITY assuring the dignity of the individual and the 2[unity and integrity of the Nation];

IN OUR CONSTITUENT ASSEMBLY this twenty-sixth day of November, 1949, do HEREBY ADOPT,ENACT AND GIVE TO OURSELVES THIS CONSTITUTION.

1. Subs. by the Constitution (Forty-Second Amendment) Act. 1976, sec.2, for "Sovereign Democratic Republic(w.e.f. 3.1.1977)

2. Subs. by the Constitution (Forty-Second Amendment) Act. 1976, sec.2, for 'unity of the Nation (w.e.f.3.1.1977)

THE CONSTITUTION OF INDIAChapter IV

A Fundamental Duties

ARTICLE 51 A

Fundamental Duties. It SHALL be the duty of every citizen of India

(a) to abide by the Constitution and respect its ideals and institutions, the National Flag and theNational Anthem;

(b) to cherish and follow the noble ideals which inspired our national struggle for freedom;

(c) to uphold and protect the sovereignty, unity and integrity of India;

(d) to defend the country and render national service when called upon to do so;

(e) To promote harmony and the spirit of common brotherhood amongst all the people of Indiatranscending religious, linguistic and regional or sectional diversities; to renounce practicesderogatory to the dignity of women;

(f) to value and preserve the rich heritage of our composite culture;

(g) to protect and improve the natural environment including forests, lakes, rivers, wild life and tohave compassion for living creatures;

(h) to develop the scientific temper, humanism and the spirit of inquiry and reform;

(i) to safeguard public property and to abjure violence;

(j) to strive towards excellence in all spheres of individual and collective activity so that the nationconstantly rises to higher levels of endeavour and achievement.

*(k) a parent or guardian to provide opportunities for education to his child or as the case may be wardbetween the age of six and fourteen years.

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CHAPTER - 1

Introduction to Horticulture 1-6

CHAPTER - 2Importance of Horticultural Crops 7-14

CHAPTER - 3Principles of Horticulture Crop Production Technology 15-30

CHAPTER - 4Principles of Plant Propagation, Methods of Propagationfor Horticultural Crops 31-55

CHAPTER - 5Essential Plant Nutrients, their Deficiency Symptoms andToxicities in Horticultural Crops 56-65

CHAPTER - 6Organic and inorganic manures and their methods ofapplication in horticultural crops 66-80

CHAPTER - 7Water Management in Horticultural Crops 81-87

CHAPTER - 8Weed Management in Horticultural Crops 88-103

CHAPTER - 9Major Pest and Diseases Management in Horticultural Crops 104-109

CHAPTER - 10Harvesting, Handling and Storage of Horticultural Crops 110-123

CHAPTER - 11Traits and Quality Standards of Horticultural Produce 124-131

Contents

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Introduction to HorticultureOBJECTIVES

After studying this chapter, students will be able to:

• Learn about the inception of horticulture and its distinguishing features

• Know about the various branches of Horticulture

INTRODUCTION

Horticultural Science is an exciting discipline with a variety of study areas and possiblecareers. Not sure what horticulture is? Did you eat any fruits or vegetables today? Enjoy beautifullandscaping in a park? Play golf at a well-managed course?

Horticulture affects everyone. It plays a very important role in society influencing ourlifestyle and general health in many ways. This includes the production of fruit and vegetableswhich form a vital ingredient of our daily diet and the development of pleasant surroundingsfor living and working, which create positive effects for emotional health. In this chapter, wewill discuss about horticulture, its distinguishing features and branches based on the cropsdealt.

WHAT IS HORTICULTURE?

According to Liberty Hyde Bailey, one of the most famous American scholars of horticulture,"Horticulture is the growing of flowers, fruits and vegetables, and of plants for ornament andfancy."

Horticulture is defined by Webster'sdictionary as "the science and art of growingfruits, vegetables, and flowers." It is theintensive commercial production of high-value and high-yielding plants. But it alsoincludes the cultivation of garden crops andlandscape ornamentals and the interaction ofscience and art. Horticulture contributes to the economy, provides good nutrition, and is a valuablespiritual and psychological therapy. Horticulture beautifies and enhances the environment.

The term Horticulture is derived from twoLatin words i.e. Hortus meaning garden orenclosure and Colere meaning to grow or tocultivate. Garden in itself is a broad term.Garden is originated from the latin termGyrdan meaning ‘to enclose’.

CHAPTER 1CHAPTER 1

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The term Agriculture refers broadly to the technology of raising plants and animals .On theother hand, Horticulture which is a part of agriculture is concerned with the raising of gardencrops.. Horticulture can also be defined as the branch of agriculture concerned with intensivelycultivated plants directly used by man for food, medicinal or aesthetic purposes.

In olden days, food crops like Paddy, Maize, and Wheat etc. were grown in open fields ona large scale, while some crops of special interest like fruits, vegetables, flowers etc. were grownin the back yard of houses in an enclosure. In cases where fruits, vegetables and flowers weregrown in areas other than backyards, they are protected by erecting walls, by raising live fences,non-live fences etc. i.e. they are enclosed. As such, the term Horticulture in the original sensereferred to the cultivation of crops with in the protected enclosure, which is often called as agarden (Crops grown in a protectedenclosure). So, the culture of crops in gardensis referred as Horticulture.

At present, fruits, vegetables, flowers etc. are grown not only with in the back yards, butalso in large areas in open fields on a commercial scale. Traditionally garden crops includefruits, vegetables and flowers. But today's horticulture deals not only with the fruits, vegetablesand flowers but also with other important crops like spices, condiments, plantation crops,medicinal and aromatic plants etc,. Besides cultivation of these crops, present day horticulturealso deals with the utilization and improvement of these crops. Hence, modern horticulturemay be defined as a part of agricultural science, which deals with the production, utilization,and improvement of fruits, vegetables, flowers, ornamentals, plantation crops, medicinal andaromatic plants etc.

MAIN DISTINGUISHING FEATURES OF HORTICULTURE

i. Horticulture crops are used in a living state while others like grains etc. are not usedin a living state.

ii. Horticulture crops are comparatively more intensively cultivated than field crops.

iii. Horticulture crops have high water content.

DIVISIONS OF HORTICULTURE

Horticulture is divided in to the following divisions for convenience based upon the cropsdealt and also their purpose and utilization

1. Pomology: It is derived from two words i.e. Pomum meaning fruit and Logos meaningdiscourse or study. Therefore, pomology is study or cultivation of fruit crops such as Mango,

When fruits are grown in a definite area then thatpart is called as an Orchard

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Litchi, Citrus, Sapota, Guava, Grape, Banana, Pineapple, Apple, Pear, Peach, Plum andCherry etc.

2. Olericulture: It is derived from two words i.e. Oleris meaning Potherb and Cultra meaningcultivation. Therefore, olericulture literally means potherb cultivation of Brinjal, Okra,Tomato, Capsicum, Peas, Beans, Cucurbits etc.

3. Floriculture: It is derived from two words i.e. Florus meaning flower and Cultra meaningcultivation. Therefore, floriculture means study of flower crops such as Rose, Jasmine,Carnation, Aster, Marigold, Dahlia, Zinnia, Cosmos, Hibiscus, Balsam, Poinsettia,Hollyhock, Gerbera, and Gaillardia etc.

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4. Landscape gardening: It deals with the planning and execution of ornamental gardens,parks, landscape gardens etc.

5. Post harvest technology: It deals with the processing and preservation of produce ofhorticulture crops.

6. Plantation crops: These crops are cultivated in an extensive scale in large contiguous areas,owned and managed by an individual or a company and whose produce is utilized onlyafter processing. Coffee, Tea, Rubber, Coconut, Cocoa etc. are some of the importantplantation crops.

7. Spices and condiments: This branch deals with the cultivation of crops whose produce isused mainly for seasoning and flavouring dishes.

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Spices: These are those plants the products of which are made use of as food adjuncts toadd aroma and flavour. For example, Pepper, Cardamom, Clove, Cinnamon, etc.

Condiments: These are those plants the products of which are made use of as food adjunctsto add taste only. For example,Turmeric, Ginger, Red chillies, Onion, Garlic etc.

8. Medicinal and aromatic plants: It deals with the cultivation of medicinal plants, whichprovide drugs and aromatic crops which yields aromatic (essential) oils.

Medicinal plants: These plants are rich in secondary metabolites and are potential sourcesof drugs. The secondary metabolites include alkaloids, glycosides, coumarins, flavonoidesand steroids etc. Important medicinal plants are Periwinkle, Opium, Menthi, Cinchona,Dioscorea Yam, Belladona, Senna, Sarpagandha, Aswagandha, Tulasi etc.

Aromatic plants: These plants possess essential oils in them. The essential oils are theodoriferous steam volatile constituents of aromatic plants. Lemon grass, Citronella,Palmrosa, Vetiver, Geranium, Davanam, Lavendor etc. are some of the aromatic plants

ACTIVITY/EXERCISE

Visit an orchard, vegetable farm, landscape garden and a processing unit. Observe andwrite the differences in the respective specialized vocations being dealt. Further make your

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observations on the use of spices and condiments in Indianfoods._________________________________________________________________________________

CHECK YOUR PROGRESS

1) Define horticulture? Write the distinguishing features of horticulture crops.

2) Enlist the various divisions of horticulture. Differentiate between pomology and olericulture.

3) How do fruit crops differ from plantation crops?

FILL IN THE BLANKS

1. The word 'Horticulture' consists of two parts namely ……………and ……………..

2. Garden is originated from the latin term Gyrdan meaning ………………

3. A branch of horticulture which deals with the planning and execution of ornamentalgardens, parks, landscape gardens etc. is referred to as ……………………………….

4. Medicinal plants are rich source of ………………………….

5. Aromatic plants possess…………………..in them.

SUGGESTED FURTHER READINGS

Bal, J.S. (2007). Fruit growing Kalyani Publishers,Ludhiana, India.

Chattopadhyay, T.K. (2012). A textbook on Pomology, Vol. 1 (Fundamentals), Kalyani publishers,Ludhiana, India.,

Singh, J. (2012). Basic Horticulture. Kalyani publishers, Ludhiana, India.,

http://www.angrau.ac.in/

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Importance of HorticulturalCrops

OBJECTIVES


• Explain the importance of horticultural crops in day-to-day life of human beings andits impact on national economy

• Develop an appreciation of nature and the environment

INTRODUCTION

Do you know it is dangerous to your health if the right content of food is not consumed?Well, let's face it. Bad eating habit(s) contributes about 35 -40 per cent of death globally.

Several diseases are also associated with imbalanced diet. That is why it is important forone to know the right food to eat at the right time. It may sound needless to talk about this assome of us pretend we already know the health benefits of eating fruits and vegetables, yet, howwell do we do as people to practice it? How often do we do this? That is why, as human as weare, it is important we keep reminding ourselves in order not to deviate. Fruits and vegetablesare essential building blocks of any diet. Not only are they loaded with vitamins and mineralswhich are essential for healthy living, but also satisfy you as part of balanceddiet. By increasingan intake of fruits and vegetables, one is gradually reducing the risk of becoming ill, as thiswould boost the immune system as well as building resistance to common diseases and infectionslike: cardio-vascular diseases, kidney failure, stroke, hole-in-heart, and osteoporosis amongothers. Furthermore, it leaves you looking better and feeling great, as part of a healthy diet,which can be an all-round improvement for your well-being.

For the economy to flourish there must be an increase in productivity which highly dependson a healthy working force. The alternative is an increase in fruits and vegetable consumption.Thisis because of the natural goodness contained within these ultimate healthy foods that will providethe necessary energy to fuel you through the day and give you the drive and determination toprogress through a course exercise to improve overall fitness.

Having said that, fruits can act as a substitute for sugary snacks, which otherwise depleteenergy and lead to numerous other health problems.The natural sugar contained in fruits is

CHAPTER 2CHAPTER 2

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essential for the effective maintenance of the immune system and the body's natural defensemechanisms, as well as increasing fruits in the diet as a healthy snacking alternative.

Vegetables on the other hand, should account for a substantial proportion of each meal, toultimately improve your diet and by ensuring a substantial role they play within your diet; youshould end up seeing the benefits in your skin, hair and general health. On top of this, an increasein fruit and vegetable intake can leave you feeling physically better and more alert, increasingattention span and reducing fatigue. However, fruit consumption may have a side effect if notproperly washed and rinsed and vegetables as well, if not well cooked. Therefore, maximumattention must be given to its preparation to avoid any damaging effect. Why not try introducingmore vegetables and fruits into your diet today by doing a straight swap of fruits for sugarysnacks and introducing vegetables to boost any meal as part of a nutritious and healthy balanceddiet.

Fruit and vegetables have long been touted for their health benefits. In India, the virtues ofhorticulture now include the ability to lift rural communities out of poverty.

IMPORTANCE OF HORTICULTURAL CROPS IN HUMAN DIET

From human nutrition point of view, horticulture is most important to our daily living.Many of the horticulture crops and their products find place in our meals and diet. Human bodyrequires vitamins, minerals, proteins, energy etc. for its health. All these are supplied byhorticultural crops. Fruits and vegetables are the chief sources of vitamins, minerals,carbohydrates, fats, proteins etc. are recognized as protective foods as they are necessary for themaintenance of human health. No doubt these can be obtained by consuming meat, fish, egg etc.but for vegetarians the consuming of vegetables and fruits is the only solution for getting theseessential nutrients for making a sound body with appropriate health.

Deficiency of any minerals andnutrients is depicted by the humanbody by giving typical symptoms.The great majority of people obtain mostof their carbohydrates and proteins fromcereals and pulses but their diets must alsocontain significant amount of fruits andvegetables to ensure that they get thevitamins which are not provided by thestaple cereal foods.

A person should consume atleast120 g of fruits and 300g vegetables per day as per Indian Council of MedicalResearch, but the consumption of fruits and vegetablesper capta in India is still low. However, the respectiveavailability of fruit and vegetables is 172 g and 350 gper day in our country. In countries like Italy, France andUSA the consumption is 308, 232 and 223 g / dayrespectively.

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Vitamins: These are the important constituents of fruits and vegetables and areindispensable part of human diet. Although required in very minute quantities, they are absolutelyessential for the maintenance of health. The deficiency of any vitamin from the diet for considerableperiod may lead to diseased state or disorder conditions. Fruits and vegetables supply severalvitamins.

Vitamin-A: It is essential for normal growth, reproduction and maintenance of health andvigour. It affords protection against cold and influenza and prevents night blindness. Thedeficiency of this vitamin results in cessation of growth in young children, night blindness, dryingup of tear glands in the eyes, eruption of skin (Rashes on the skin) and brittleness of the teeth

Sources: Fruits-Mango, Papaya, Dates, Jackfruit, Walnut etc. Vegetables-Greens like palak,spinach, amaranthus, fenugreek, carrot, cabbage, lettuce, peas, tomato etc.

Vitamin B1 (Thiamine) : Tones the nervous system and helps in proper functioning of thedigestive tract. Its deficiency in human diet results in Beri-beri, paralysis, loss of sensitivity ofskin, enlargement of heart, loss of appetite ,loss of weight and fall in body temperature.

Sources: Fruits-Orange, pineapple, jack fruit, cashew nut, walnut, dry apricot, almond,banana etc,. Vegetables-Green chilli, beans, onion, sweet potato, tomato (red), leaves of colocasia.

Vitamin B2 (Riboflavin): This vitamin is required for body growth and health of the skin.The deficiency of this vitamin causes sore throat, anorexia cataract, and loss of appetite andbody weight and also development of swollen nose.

Sources: Fruits- Bael, papaya, litchi, banana, apricot, pomegranate, pear etc. Vegetables-Cabbage, cauliflower, potato, peas and beans, methi, lettuce, asparagus, green chillies, leafyvegetables etc,.

Vitamin -C (Ascorbic Acid): Thisvitamin promotes general health and healthygums, prevents scurvy disease which ischaracterized by pain in the joints andswelling of limbs (rheumatism), bleeding ofgums, tooth decay and keeps the bloodvessels in good condition.

Sources: Fruits: Amla, guava, ber, citrus, strawberry, pineapple etc. Vegetables: Tomato,palak, menthi, cabbage, green chillies, spinach, potatoes, peas and beans and carrot etc,.

Vitamin-D: This vitamin is necessary for building up of bones, preventing rickets anddiseases of teeth.

Antioxidants are naturally occurring substancesfound in most plants and have the potential to helpcombat heart diseases and fight cancer

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Sources: All green leafy vegetables are rich in this vitamin.

Vitamin-E: Ithas an important effect on the generative functions and promotes fertility.

Sources: Green lettuce and other green vegetables, as well as almonds, cashewnut, walnutetc.

Vitamin-K: This vitamin prevents blood clotting.

Sources: All green leafy vegetables and nuts are rich in this vitamin.

Minerals: Human body requires minerals like P, Ca, Iron, and Iodine etc. for maintaininggood health.

Calcium: It is essential for development of bones, regulation of heartbeat, controlling bloodclots.

Sources: Fruits- Acid lime, Orange, Fig, Dried apricots, wood apple etc. Vegetables-Cabbage, greens, beans, carrot, onions, peas, tomatoes, agati, spinach drumstick leaves etc.

Iron: It is required for production of haemoglobin and it is constituent of red bloodcorpuscles. Its deficiency causes anaemia, smooth tongue, pale lips, eyes and skin and frequentexhaustion.

Sources: Fruits- Custard apple, Guava, Pineapple, Straw berry, Grape, Black currents, drieddates etc. and Vegetables like Carrot, Drumstick leaves, beans and agave etc.

Phosphorus: It is essential for maintaining the moisture content of tissues and fordevelopment of bones.

Sources: Fruits-Guava, Grape, Jackfruit, Passion fruit, Orange and vegetables like Carrot,Chilli, Drumstick leaves, Beans, cucumber and onion.

Proteins: These are body building foods. These are essential for growth of the body. Thedeficiency of proteins in the body causes retarded growth and increases susceptibility to diseasesand causes lethargy.

Sources: Fruits- Cashewnut, almond, pecannut, walnut etc. Vegetables like peas and beansare rich in proteins.

Enzymes: These are required for controlling several metabolic activities in the body.

Sources: Papaya-Papain and Pineapple-Bromelin.

Fibre and roughages (Cellulose and pectin): Fruits and vegetables supply roughages. Theseare required for digestion and prevention of constipation.

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Presently, the horticulture sector contributesaround 31 % of the GDP and 38% of the totalexports of agricultural commodities fromaround 14% of area.

o Globally, second largest producer of fruitsand vegetables

o Largest producer of mango, banana,coconut, cashew, papaya, pomegranate etc.

o Largest producer and exporter of spiceso Ranks first in productivity of grapes,

banana, cassava, peas, papaya etc.

Sources: Fruits contain low content of fibre. Guava and anola are better sources comparedto other fruits. Leafy vegetables are rich in fibre content

Energy foods: Fruits and vegetables contain Carbohydrates and fats there by supply energyto human body. Those fruits (Banana, Dates, Apple etc.) and vegetables (Potatoes, Sweet potato,Beans, Peas etc.), which contain carbohydrates, are called as energy foods. Nut fruits like Walnut,Cashew nut and almond etc. supply proteins besides energy.

IMPORTANCE OF HORTICULTURE IN THE NATIONAL ECONOMY

India is the 2nd largest producer in the world, with 76 million tones of fruits occupying anarea of 6.70 million hectare and 156 million tones of vegetables from an area of 8.98 millionhectare. In all, horticulture crops occupy anarea of 23 million hectare and are said toannually yield 257million tones of crops.Horticulture sector not only impact theimmediate life but play a very important rolein the Indian economy by proving to be an important source of income for the rural population.Fruits and vegetables are not only used for domestic consumption and processing into variousproducts(Pickles, preserves sauces, jam, jelly squashes, etc.) but also substantial quantities areexported in fresh and processed form,bringing much-needed foreign exchange forthe country. These groups of crops alsoprovide ample scope for achieving bio-diversity and diversification to maintainecological balance and to create sustainableagriculture and can make an impact on thenational economy in the years to come.

Table: Area and production of Horticultural Crops.

Particulars Area (million hectare) Production (million tones)Fruits 6.70 76.4Vegetables 8.98 156.3Flowers 0.25 76.7Plantation Crops 3.58 16.36Spices 3.21 5.95Aromatic Plants 0.50 0.56Total 23.22 257.3Source: www.nhb.org.in

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Export growth of fresh fruits and vegetablesin term of value is 14% and of processed fruitsand vegetables is 16.27%

1. Horticultural produces contribute to national wealth. They are the important exportablecommodities in many countries. Through export of horticultural produce, our country isearning foreign exchange. India is exporting flowers to America, Netherlands, Germany,Japan, UK; Onionsto Malayasia, UAE, Singapore, Sri Lanka and Bangladesh; vegetables toSri Lanka, America, UAE, Spain, SaudiArabia, Bangladesh, U.K., Kuawait,; Freshgrapes to UK,Netherlands, UAE,Bangladesh, Germany; Fresh fruits toBangladesh, UAE, Saudi Arabia, UK and SriLanka.; Processed vegetables to Egypt, Srilanka, UAE, America and Turkey and Mangopulp to Saudi Arabia, UAE, Netherlands, Kuwait and Germany and Pickles and Chutneysto UK, America, UAE, Spain etc.

Table: Export of Horticulture Produce in India (APEDA Website)

Product Quantity (MT) Value (Rs. Lakhs)Floriculture 30926.02 36532.15Fruits / Vegetable Seeds 15205.81 28776.35Fresh Onions 1309924.82 172299.80Other Fresh Vegetables 729810.62 129893.77Walnut 5841.56 23108.40Fresh Mangoes 63441.29 20974.30Fresh Grapes 108584.56 60288.15Other Fresh Fruits 271347.82 73586.20Dried and Preserved Vegetables 138464.03 70018.80Mango Pulp 150499.06 62082.91Other Processed Fruits & Vegetables 459514.68 211785.85

2. Increased production of horticulture crops is possible in comparison to other agronomicalcrops because trees have a longer life and their production increases with advancementin age provided a proper care is taken. Similarly vegetables can also be grown 3 to 4times each year giving the products all the time they are grown. More number of cropscan be grown from same piece of land, whereas, cereal crops bind the land for a longertime. Furthermore, spices, medicinal, aromatic and flower crops are high value crops asthese crops fetch more prices in the market.

3. Horticultural crops are more profitable since the average income per unit area is more incomparison to agriculture crops. One hectare area of horticultural crops may generateincome to the tune of Rs. 10,000 to Rs. 1,00,000 and even more, depending upon nature andvalue of crops.

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4. With the support of horticulture, many agro-industries can spring up in villages itself. It isan acceptable fact that horticulture can come in a big way to solve the problem ofunemployment. Source of other industries such as rubber, oil, gum, dyes, chemicals etc.raw material for fruit and vegetable-processing plants, hence becomes a solution to reduceunemployment.

5. Horticultural crops provide gainful employment for small farmers and agricultural labourin doing field operations like fruit picking / harvesting, grading, packing, selling etc.throughout the year. One hectare of fruit production generates 860 man-days per annum as against143 man-days for cereal crops. Some industrial attribute crops and cultural intensive cropslike grape, banana and pineapple, generate much large employment ranging from 1,000 to2,500 man-days per hectare. The processing industries are labor intensive and offer highemployment potential in collection centers, grading, packing, loading / unloading, storages(ware houses and cold storages) transport, marketing and processing units.

Entertainment

Roaming in the gardens, orchards or places well planted with flowerbeds etc. gives mentalpeace to the people. One enjoys fresh air and natural beauty, sheds of tension making him fresh.Paradise means garden. The hanging garden of Babylon (one of the 7th wonders of the world)and the Versailles garden of 17th century are unique examples.

Medicines

The parts like stem, leaf, flowers, roots and even the fruits of horticulture plants are used tomake drugs, chemicals, insecticides, germicides etc. For example, rose water is used to cureeyes ailments. Similarly saffron is imported ingredient of many medicines, papain is a digestiveenzyme, citrus fruit like sweet lime is used for liver ailment, rind of pomegranate and pectinfrom guava used for stomach upset, bark of arjun trees for heart troubles, neem water for skinirritation and allergies etc.

Aesthetic value and religious importance

Aesthetic value and religious importance is the unique factor distinguishing it fromagricultural activities. Mango leaves, wood, banana leaves etc. are used for religious functions.Similarly the plantation of banana tree in the court yard or tulsi plantation is said to bringprosperity as per Hindu religion. Leaves of bael are famous for offering to Lord Shiva. Worshipingtree is considered pilgrimic action. This aspect of horticulture has lead to its universal popularity.

ACTIVITY/EXERCISE

Make a check list of fruits and vegetables being consumed by you in your daily diet andwrite the observations on the important fruits and vegetables required to meet daily requirementfrom nutrition point of view.

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CHECK YOUR PROGRESS1) Fruits and vegetables are protective food. Justify the statement.

2) What is the importance of horticulture in Indian economy?

3) Write an account on the medicinal properties of horticultural crops.

4) Discuss in brief the importance of fruits in daily diet of human beings.

5) Identify the causes due to which the following disorders develop and enlist the fruits andvegetables as their remedial measures:

Sr. No. Disorder Causes Remedial measures1. Paralysis2. Pain in joints and

swelling of limbs3. Night blindness4. Sore throat, loss of appetite5. Anaemia

FILL IN THE BLANKS1. Per capita consumption of fruits and vegetables in India is …………g and …………g

respectively.

2. Night blindness is due to the deficiency of………………….and can be corrected by taking………………………………..fruits and vegetables.

3. Energy providing fruits are ……………. and ………………………………

4. ………………vitamin prevents blood clotting.

5. India is the largest producer and exporter of ………………………….

6. Total area under fruits in India is ………… and production is…………………

7. India ranks ………………in the production of fruits and vegetables.

8. ……………..and………………are required for digestion and prevention of constipation.

9. Proteins are called as ……………………….food.

10. ………………fruit is the richest source of vitamin C and can be used to avoid scurvy.

SUGGESTED FURTHER READINGSBal, J.S. (2007). Fruit growing Kalyani Publishers,Ludhiana, India.



http://www.angrau.ac.in

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Principles of Horticulture CropProduction Technology

OBJECTIVES


• Select the appropriate location for raising desirable horticultural crops under a givenclimatic conditions.

• Select the suitable lay out plans for different horticultural crops.

• Plan various key operations for establishing new orchard/garden.

• Manage the horticultural crops by making efficient uses of available resources.

• Decide on the most appropriate cultivation system for a given situation.

INTRODUCTION

As you might be aware after studying chapter I that, 'Horticulture' deals with a large numberof plant species. Traditionally, it includes fruits, vegetables, and ornamental plants. It dealswith a combination of the botanical and agricultural aspects of plants. Thus, one may definehorticulture as the culture and biology of garden crops, including both the aesthetic and thescientific dimensions. Basic principles of physics, chemistry, and biology are used byhorticulturists to understand and manipulate plant life. Therefore, it is essential to understandthe fundamental principles of horticultural crop production in order to grow them successfullyand fetch economic returns.

PRINCIPLES OF FRUIT PRODUCTION

The commercial production of fruits is known as orcharding. Grape plantations are calledvineyards, and the cultivation of grapes is called viticulture. Similarly, citrus orchards are typicallycalled citrus groves and the cultivation of citrus is known as citriculture. Orcharding and othertypes of fruit growing require high capital investment for years on a fixed site, without immediatereturn.

SELECTION OF SITE

Selection of suitable site is the first step for establishing an orchard on commercial scale.Selection may be made based on the following criteria;

CHAPTER 3CHAPTER 3

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• The land chosen for orchard should be in proximity to main road and market.

• It should have proper irrigation facilities and have a good soil and climate suitablefor growth and production of fruit trees.

• Experience of the fruit growers and research stations in the locality should be takeninto account for the acclimatization of the fruits under consideration.

• Adequate water supply should be available round the year.

Any mistake in selection of site cannot be altered after planting while modifications inother factors are possible.

Preliminary Operations for establishing an orchard

After selecting the suitable location and site, some preliminary operations have to bedone. Trees are felled without leaving stumps or roots. The shrubs and other weedy growthare also cleared. Deep ploughing is essential to remove big roots. The land should bethoroughly ploughed, leveled and manured. Leveling is important for economy of irrigationand preventing soil wash. In the hills, the land should be divided into terraces dependingupon the topography of the land and the leveling is done within the terraces. Terracing protectsthe land from erosion. If the soil is poor, it would be advisable to grow a green manure cropand plough it in situ so as to improve its physical and chemical conditions before plantingoperations are taken up.

Planning of an orchard

A careful plan of the orchard is necessary for the most efficient and economic management.The following points should be considered in preparing the plan.

1. Optimum spacing to accommodate maximum number of trees per unit area.

2. Stores and office building in the orchard should be constructed at the centre for propersupervision. .

3. Wells should be located at convenient places in different parts at the rate of one well for 2to 4 hectares.

4. Each kind of fruit should be planted in a separate block.

5. Fruits ripening at the same time should be grouped together.

6. Pollinizers should be provided in deciduous fruits.

7. Irrigation channels should be laid along the gradients for most economical conduct of water.

For every 30m length of channel, 7.5 cm slope should be given.

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8. Roads should occupy minimum space for the economy of transport. The clearance betweenwind break and first row of trees is advantageous for the road.

9. Short growing trees should be allotted at the front and tall at the back for easy watchingand to improve the appearance.

10. Evergreen trees should be in the front and deciduous ones behind.

11. Fruits attracting birds and animals should be close to the watchman's shed.

12. A good fence is essential. Live fencing is economic and cheap to other kind of fences. Theplants suitable for live fencing should be drought resistant, easy to propagate from seed,quick growing, have dense foliage, should stand severe pruning and should be thorny.Agave, Prosopis juliflora, Pithecolobium dulce and Thevetia if closely planted in 3 rows wouldserve as a good live fencing.

13. Wind breaks, rows of tall trees planted close together around the orchard, are essential toresist velocity of wind which causes severe ill-effects particularly moisture evaporationfrom the soil. Since the wind breaks are very effective in reducing the wind velocity andminimizing the damage to the fruit trees and to other crops, their presence in regions wherestrong winds prevail is of paramount importance. A wind break ordinarily has its maximumeffectiveness for a distance about four times as great as its height but has some effect overtwice about that distance.

The most effective windbreak is a double row of tall trees alternately placed. There shouldbe at least as much as space between the windbreak and the first row of the fruit trees as betweenfruit trees. It is preferable to dig a trench of 90 cm deep at a distance of 3m from the windbreak treesand prune and cut all the roots exposed and again fill up the trenches. This may be repeated forevery 3 or 4 years in order to avoid the competition between the wind breaks and fruit trees formoisture and nutrition. Trees suitable for windbreak should be erect, tall and quick growing,hardy and drought resistant and mechanically strong and dense to offer maximum resistance towind. The trees which are suitable for growing as wind breaks are Casuarina equisetifolia, Pterospermumacerifolium, Polyalthia longifolia, Eucalyptus globulus, Grevillea robusta, Azadirachta indica etc.

LAYOUT SYSTEMS OF PLANTING

Lay-out means locating the position of trees, roads and buildings in the orchard beingestablished, and systems of lay-out refer to the orderly ways of planting the trees. It is desirableto have the trees planted in systematic way because

• Orchard operations like interculture and irrigation are carried out easily.

• It enables equal distribution of area under each tree.

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• It results in least wastage of land.

• It makes supervision more easy and effective.

• There is room for systematic extension of the orchard.

There are mainly five systems of planting of fruit trees. In all these systems, trees are plantedin rows.

A. Square system

In square system the trees are planted in four corners of asquare keeping the same distance between row to row and plant toplant in the same row. This is the most commonly followed systemand is very easy to layout. This system permits inter cropping andcultivation in two directions.

B. Rectangular system

In rectangular system the trees are planted in the same way as ina square system except that the distance between rows to row will bemore than the distance between plant to plant in the same row. Thewider alley spaces available between rows of trees permit easyintercultural operations and even the use of mechanical operations.

C. Quincunx or Diagonal system

Basically, quincunx or diagonal system is the same as the squaresystem except for the addition of a tree in the center of each square. Thiswill accommodate double the number of plants, but does not provideequal spacing. The central trees are known as filler crop and the others asmain crop. The central (filler) tree chosen may be a short lived one. Papaya,Guava, Lime, plum and peaches are a few examples of filler crops in orchards with trees likemango, jackfruit and tamarind. This system can be followed when the distance between thepermanent trees is more than 10m. As there will be competition between permanent and fillertrees, the filler trees should be removed after a few years when main trees come to bearing.

D. Hexagonal/ septuple system

In the hexagonal system, the trees are planted at the corners of anequilateral triangle. Six such triangles are joined together to form ahexagon. Six trees are positioned at the corners of this hexagon with aseventh in the center all arranged in the three rows.This system provides

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equal spacing but it is difficult to layout. This system accommodates 15% more trees than thesquare system. The limitations of this system are that it is difficult to layout and the cultivationis not so easily done as in the square system.

E. Contour system

In a hilly area, a lot of depressions, ridges, furrows and place surface are found. But whenplating is done a line is made by connecting all the points of same elevation across the slopefrom a base line. Thus spacing is maintained on this row.

The main purpose of this system is to minimize land erosion and to conserve soil moistureso as to make the slope fit for growing fruits and plantation crops. Terrace system on the otherhand refers to planting in flat strip of land formed across a sloping side of a hill, lying levelalong the contours. Terraced fields rise in steps one above the other and help to bring more areainto productive use and also to prevent soil erosion. The width of the contour terrace variesaccording to the nature of the slope. If the slope becomes stiff, the width of terrace is narrowerand vice-versa. The planting distance under the contour system may not be uniform.

In the recent past, a new trend has been observed among the growers i.e. adoption of highdensity planting system. This has gradually becoming imperative due to shortage of land andlabour.

High density planting system

High density planting (HDP) can be defined as "accommodation of the maximum possiblenumber of the plants per unit area to get the maximum possible profit per unit of tree volumewithout impairing the soil fertility status". This technique was first established in apple in Europeduring sixties and now majority of the apple orchards in Europe, America, Australia and NewZealand are grown under this system.

Examples of successful HDP in fruit crops: There are quite a good number of successstories of HDP in fruit crops under Indian conditions. Some of them are being listed below withtheir technical details;

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Table 1. Performance of fruit crops under HDP.

S. No. Crop Variety Density Spacing (m) Yield (t/ha)(Plants/ha)

1. Banana Basarai 4,444 1.5x1.5 78.0

2. Papaya PusaNanha 6,400 1.25x1.25 103.6

3. Pineapple Kew 63,758 0.22x0.6x0.75 118.8

4. Guava Lalit 5,000 1x2 55

5. Mango Amrapali 1,600 2.5x2.5 22

CHOICE OF FRUIT TREES

The next step of orchard establishment is choice of fruit crops. The choice of fruit crops isgoverned by various soil and climatic conditions as indicated in Table 2;

Table 2. Choice of fruit crop as affected by soil and climatic conditions.

Climatic/soils conditionsClimatic conditionsTemperate region Apple, pear, peach, walnut, apricot, almond etc.Tropical region Papaya, banana, sapota, coconut, cashewnut,

mangosteen, citrusSubtropical region Mango, litchi, pomegranate, loquat, grape,

pomegranateTemperate fruits in subtropical region Low chilling peaches, apples, plums and pearsArid region Ber, bael, mulberry, aonla, date palm, phalsa etc.Semi-arid region Jamun, woodapple, fig, custard apple, khirniCold desert Apricot, Pistachionut, apple, chilgoza, prunesCold sandy desert Chilgoza nutArid temperate zone OleasterSoil conditionsCoastal sands CoconutSandy soils Ber, date palm, fig, mulberry, phalsaLoamy soils Most of the major fruit cropsClayee soils JamunAlkaline soils Guava, date palm, coconut, olive, phalsaAcidic soils Raspberry, blueberry, fig, gooseberrySalt affected soils Date palm, ber, aonla, bael

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All major fruits are clonally propagated by means of cutting, grafting, budding andmicropropagation. In modern orcharding, fruit crops are grown as a composite plant. The upperpart, which forms aerial part is called as scion, while the lower part, which makes the root systemis termed as rootstock. In some cases a third part i.e. interstock, which is used for overcomingincompatibility between the scion and stock is also employed. In most cases, the commercialvarieties are used as scion, and the rootstock is of a different species or variety. Rootstocks areknown to influence vigour, yield, early bearing, fruit size, and impart tolerance to various soil,climatic and pests & diseases. Some of the important rootstocks of fruit crops are being mentionedbelow;

Table 3. Rootstocks of fruit crops.

Fruit crop Rootstocks

Apple M9, M27, MM111, MM106

Ber Jharber (Ziziphusnummularia), Boradi (Z. rotundifolia)

Citrus Rangpur lime, KarnaKhatta, Rough lemon, Trifoliate orange, Flying Dragon

Grape Salt Creek, Dogridge, Ripario, Temple

Guava Psidium friedrichsthalianum, P. pumilum

Mango Kurukkan, Olour, Vellaikolmban

Sapota Khirni

Walnut Paradox (Juglans hindsi x J. regia)

Fig Ficus glomerata

Spacing

The distance between trees and rows varies with climatic conditions, soil type, rootstock,cultural practices, training & pruning, system of planting, fruit crop and varieties to be planted.The most commonly followed spacing for commercial fruit crops are given below;

Spacing (m) Tree number/hactare Fruit crop

2x2 2500 Dwarf papaya, dwarf banana

3x3 1111 Tall papaya, Tall banana, grape

4x4 625 Hazel nut

5x5 400 Peach, pomegranate

6x6 277 Citrus, apricot, almond

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7x7 204 Plum, guava

8x8 156 Aonla, ber, bael, litchi

9x9 121 Sapota

10x10 100 Mango, walnut, cherry

12x12 68 Tamarind, pecan nut, jamun

Farm operations like pruning and training of trees and thinning of fruits are unique topomology and are regular features of an orchard.

Training: It is a physical technique that control the shape, size, and direction of plant growth

Pruning: It is a judicious removal of plant part to improve shape, influence growth, improveflowering, fruitfulness and fruit quality or to repair injuries.

Training systems

Training is practiced to give the shape or build strong framework of the tree in order tosupport maximum crop of good quality. Selection of training systems depends upon the agro-climatic situation of the region. Generally, three training systems viz., Open Centre or Vase,Central Leader and Modified Leader System are followed for canopy management of fruit plantsin different regions.

Orchard cultivation

Orchard cultivation refers to the careful management of the orchard soil in such a way thatthe soil is maintained in a good condition suitable to the needs of the tree with least expenses.

METHODS OF SOIL MANAGEMENT PRACTICES

a. Clean culture

This type of cultivation is extensively followed in India. This involves regular ploughingand removal of weeds.

b. Clean culture with cover crops

This type of soil management involves raising of a cover crop or green manure afterremoving the weeds. In India, green manure crops like Sunhemp, Cowpea, Daincha, Lupins etc.are more commonly used. Legume cover cropping in grape, mango, guava and other fruit cropsis becoming a common practice in the management of orchards. Cowpea and French beans growwell under guava and sapota tree.

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c. Mulching

This is one of the important soil management practices. Crop residues like straw, cottonstalks, leaves, saw dust, pine needles, coir dust arid other materials like polythene films orcertain special kinds of paper are spread in the tree basins and in inter spaces between trees.Main objective of mulching is to conserve soil moisture and to control the weed growth.

d. Sod

In this method, permanent cover of grass is raised in the orchard and no tillage is given.This type of orchard cultivation is followed in USA and Europe.

e. Sod mulch

This is similar to sod with the only difference is that the vegetation is cut frequently and thecut material is allowed to remain on the ground.

Intercropping

Most of fruit crops are a slow-growing tree and takes at least three-four years to come toflowering and fruiting. Intercrop like legumes in pre-bearing stage of trees not only providemore income but also improve health of the trees. Vegetables or leguminous crops like pulses,beans, berseem, etc. can be successfully grown during the initial stages. The recommendedintercrops for some important horticultural crops are given as under.

Crop Age Intercrop

Mango Upto 7 years Leguminous vegetables, Papaya (filler)

Grapes Upto 8 months Snake gourd or bitter gourd in pandal

Apple, pears Upto 5 years Potato, Cabbage

Banana Upto 4 months Sunhemp, onion

Tapioca Upto 3 months Onion, beans, lab-lab, black gram

Turmeric Upto 3 months Small onion, coriander

Arecanut Upto 10 years Pineapple

Coconut Upto 3 years Banana, tapioca, vegetables

Multi-tier system of cropping

The system comprise of a combination of perennial and annual plant species as differentcomponents in the same piece of land arranged in a geometry that facilitates maximum utilization

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of space in four dimensions (length, width, height and depth) leading to maximum economicproductivity of the system. Certain horticultural plants like coconut and arecanut are grown forabout 50 years in a particular land. It takes nearly 4 to 7 years for the above trees to reach thebearing stage. Adequate alley spaces (nearly 75%) are available in between these trees. Hence,these vacant spaces can be profitably used for raising other crops, thereby increasing theemployment opportunities and profit. An ideal combination of crops for multitier cropping incoconut and arecanut plantations is as follows.

Tier Crop

First (Top) Coconut or arecanut

Second Pepper trained over the trunk of coconut or arecanut trees

Third Cocoa or cloves planted at the centre of four arecanut or coconut

Fourth (ground) Pineapple, ginger and dwarf coffee

Crop regulation

Fruit crops like guava and pomegranate has three main flowering and fruiting seasons orbahars, ambebahar (spring season flowering), mrigbahar (June-July flowering) and hasthbahar(September-October flowering). Theses crops flowers continuously when watered regularly. Forcommercial production, only one crop in a year is desirable. Therefore, by crop regulation, thetree is forced to rest and thereby produces profuse blossoms and fruits during the requiredbahar. Selection of the bahar depends mainly on the availability of irrigation water, risk of damageby diseases and pests and market factors.

For bahar treatment, operations like withholding irrigations, root exposure, root pruningand spray of chemicals (thiourea, NAA or potassium iodide) are practiced to induce leaf dropand cessation of growth during the period of the unwanted bahar. The recommended doses offertilizers are applied immediately after pruning and irrigation is resumed. This leads to profuseflowering and fruiting. The fruits are ready for harvest 4-5 months after flowering.

PRINCIPLES OF VEGETABLE CULTIVATION

As compared to orcharding, the vegetable industry is characterized by its flexibility. Becausemost vegetables are grown as annuals, shifts in cultivars and crops can be readily made. Thereare three main categories of vegetable production: home gardening, market gardening, and truckgardening. In addition, there are several small, specialized production types including vegetableforcing, production for processing and seed production.

From ease in recommending the general cultivation practices, vegetable crops have alsobeen classified based on method of cultivation. In this method all the crops, which have similar

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cultural requirements are grouped together. For instance, cucurbits (musk melon, water melon,bottle gourd, ridge gourd, cucumber etc.), cole crops (cauliflower, cabbage, broccoli), root crops(beet root, carrot, radish), bulb crops (onion and garlic) not only have similar cultural requirementsfor the group but the crops in each group usually belong to same family.

There are some principles required in the production of vegetable crops which are veryimportant and well known to the grower. These principles are:

1. Production of vegetables does not involve a long time investment as does in the orchardof guava, mango, or apple.

2. Vegetable growers/farmers are not bound to produce the same crop each year likehis counterparts, who grow fruit crops.

3. Vegetable growing lacks the stability which is methodically developed over a periodof years like an orchard thus, getting into vegetable production is a fast process andgetting out may even be faster.

4. Vegetables can be grown by people with limited experience. Only skillful farmerssustain their vegetable production.

5. The land for production of vegetable crops is flexible and adjustable. It is much easierfor vegetable growers/farmers to change production from one crop to another thanfor fruit crop grower.

6. Cooperative efforts and organizations are somewhat more difficult with vegetablecrop producers than fruit growers. Vegetable/grower/farmers have no long periodfor making plans. Vegetable production is seasonal.

7. Vegetable production requires more intensive production management per unit areaand time.

Vegetable nursery raising

Most vegetable species are grown from seeds, but some important ones (e.g. pointed gourd,colocasia, basella, ivy gourd etc.) are propagated by vegetative methods. Among those grownfrom seeds, a significant number mainly those with small seeds (e.g. tomato, brinjal, cauliflower,cabbage etc.) are usually first sown in nursery beds, boxes or containers and are transplanted ata later stage. Nursery raising have several advantages like economy of seeds, uniformity ofgrowth and selection of vigorous & healthy seedlings for transplanting.

Field establishment

Land Preparation: In preparing land for vegetable production, factors such as ecologicallocation, mode of cropping, season, crop disposition, and the type of vegetables to be grown

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should be taken into consideration. The land should be first cleared off of existing vegetationfollowed by leveling and suitable tillage operations

Planting: Vegetables can be propagated either by direct sowing or by transplanting methods.

Direct sowing: Vegetables are sowed either by broadcasting or by seed drilling methods.In broadcasting, seeds are spread over the prepared land by throwing small quantities of theseeds into the air close to the surface of the prepared land. This is followed in Celosia andAmaranthus. Seed drilling method is followed for planting small seeded vegetables in rows.Shallow furrows are made at the spacing recommended for the crop and the seed drilled alongthe furrows. This method can also be used for some leafy vegetables such as Celosia andAmaranthus.

Transplanting method: Vegetable seedlings are first raised in the nursery for a requiredperiod of time before they are transplanted on the field. Seedlings are transplanted in the morningor in the evening to avoid transplanting shock.

SOME ROUTINE OPERATIONS

Thinning: Thinning of vegetable is done to reduce the number of seedlings per stand.

Supplying or gap filling: This is the practice of providing missing stands of vegetablesplanted by direct sowing as a result of poor emergence or when seedlings are damaged bypests.

Staking: This is usually required for vegetables with climbing growth habit such as flutedpumpkin, or those with weak stems such as tomato. Stake can be made from bamboo or otheravailable wood. The support allows the plant to carry more load without touching the soil thusenhancing the quality of the fruit.

Mulching: A mulch is a layer of plant residue or other materials like plastic or paper,which is applied to the surface of the soil in order to reduce evaporation, run-off or to preventweed growth. The purpose of mulching is to conserve soil moisture.

Watering: Young vegetable seedlings in the nursery or in the field should be watered inthe early morning or in the evening. Watering should be done before transplanting particularlyin the evening. Likewise, over-watering can be very harmful and can encourage the developmentof pathogenic diseases and also cause mechanical damage to the seedlings.

Fertilizer application: Vegetables must be provided with ample supplies of nutrients suchas nitrogen. Application of N fertilizer has been shown to increase yield. In some tropical leafyvegetables, fertilizers such as FYM and other sources of P and K can be applied as pre-plantbasal dressing or after the plants have become established as post planting application.

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Weeding: Weeds can be managed using cultural, physical, chemical and biological methods.Weed seeds and rhizomes can be killed using physical method during land preparation byburning. Mulching of soil can also smother weeds. Hoeing, pulling and roguing are carried outduring the early stages of growth. Chemical weed control is applied in commercially grownvegetable crops.

PRINCIPLES OF FLOWER CULTIVATION

In a garden there are certain operations that are to be followed judiciously for successfulcultivation of ornamental plants. Most of these operations, such as transplanting, pruning,pinching, etc., are of vital importance for the growth of the plants. Some other operations, suchas topiary or shearing of hedges, are designed to enhance the ornamental or aesthetic value ofthe plant material.

Some routine operations

Soil Sterilization: This is an essential operation to eliminate soil-borne diseases, causedmainly by fungi. Soil can be sterilized with 2 per cent formalin (or formaldehyde). The formalinsolution is mixed thoroughly with the soil and this is covered with tarpaulin or gunny bag for 48hours. Some fungicides such as benlate, captan, bavistin, brassicol, and blitox (0.1 to 0.2 per centsolution) are also used for soil sterilization.

Seed Sowing: Sowing of seed is an important operation for annuals, biennials, and someherbaceous perennials, as seeds of most of them are very minute and need special care duringsowing. The seeds of trees are quite bold and do not require as much care as is required forannuals.

Pricking: Pricking out, also known as thinning out, means removing the seedlings fromtheir original container and replanting into individual pots or transferring into beds to givethem more growing space.

Planting and Transplanting: Planting and transplanting are two important operations. Thetime of planting depends on the climate of the area. Deciduous plants are transplanted duringthe dormant season when they are in leafless condition. This is done only on the hills and atplaces having cold winter. The other season of planting is spring when new growth takes place,provided the plants can be given sufficient care and irrigation during the ensuing summer.Under Indian conditions, the best period is to transplant during the rainy season, provided thereis no water-logging. The pits should be dug before the rains start.

Planting of shrubs and trees: During digging the pits for planting, the surface soil shouldbe kept separately and not to be mixed with the rest of the soil. After digging the pit, the soil is

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returned to the pit mixed with the requisite quantity of manure, the surface soil going on the top.While planting, a small hole is made at the centre of the pit and the plant is placed with the ballof earth. The plant should not be placed deeper than when it was in the nursery. Aftertransplanting, the earth around the root should be finned thoroughly. A basin should be madeon the ground around the plant for watering.

Transplanting: There are generally four types of transplanting in a garden: (1) Transplantinga potted plant to ground, (2) Transferring a potted plant to another pot, (3) Potting a groundplant, and (4) Transplanting of large trees and shrubs from the ground to another suitable locationposes problems. For lifting very large trees, the help of tree-lifters or cranes and trucks will beneeded.

Shading: Shading and protection of plants is an important operation in a garden, especiallyin places having hot summers and severe winters. The newly planted seedlings or plants needshade from the scorching summer sun. In places, where frost is likely to kill the plants theseshould be given proper protection. The seedlings in the nursery also need shading.

Stopping or Pinching: The operation of pinching or stopping involves the removal of thegrowing-point of a shoot along with a few leaves. The two main purposes of this operation are toencourage branching to produce a bushy growth, and/or the production of flower-buds on thebranch which is pinched. Pinching is done mostly in annuals and herbaceous perennials and ishardly required for any flowering trees. The plants which need pinching include dahlia,chrysanthemum, carnation, brachycome and marigold.

Deshooting: Deshooting involves the removal of shoots that are not wanted. Some floweringannuals and herbaceous perennials produce numerous side shoots and if all of them are allowedto flower, the size and quality of the flowers will be greatly reduced. Deshooting of carnationsgrown for cut flower trade and chrysanthemum for exhibition purposes are common practice.

Defoliation: The removal of foliage is known as defoliation. This is done mainly with aview to induce flowering in certain plants. Sometimes, this can also be done to reduce transpirationloss during periods of moisture stress and also during transportation of certain plants such asroses. Defoliation can be achieved by the removal of leaves by hand or by the use of chemicalsand by withholding water. In jasmine, it is a common practice to defoliate the plants after pruningjust prior to the flowering season.

Staking: Plants in the garden, either in pots or on ground, need support at least for a partof, or throughout, its life. Stakes may be of various kinds. The most common stakes used in Indiaare made of either whole bamboo or split bamboo of various sizes depending upon the type ofplants to be staked. Some other types of stake which are commonly available under Indian

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conditions and can be used as stakes for herbaceous plants are the dried stems of jute, cottonand pigeon pea.

Pruning: The planned removal of branches, twigs, limbs, shoots, or roots is termed aspruning. Even the removal of a dried flower can be termed as pruning. Each pruning is donewith a view to increase the usefulness of a plant.

Wintering: This may be considered as an alternative to root pruning. In hotter parts ofIndia, it may not be wise to resort to root pruning. In such places ornamental plants are"wintered". During resting period, the water supply to the plant to be wintered is stopped fora few days and the roots are exposed to the sun by removing the surface soil around the trunk.After wintering, the roots are covered with the same soil enriched with farm yard manure andcopiously watered.

Clipping or Cutting of Hedges and Edges: To keep the hedges in symmetry, good health,and beauty, constant vigilance and regular shearing or pruning are needed. A sharp pair ofpruning shears is used for clipping the herbaceous twigs. But to cut woody branches, secateursor pruning saws will be required.

Topiary: The art of clipping and shearing shrubs and small trees and sometimes evenherbaceous perennials into ornamental or abstract shapes is known as topiary. The term is derivedfrom the ars topiaria meaning ornamental gardening. Shapes such as globe and dome can begiven without the help of any pre-fabricated moulded wire model. But difficult shapes such asbird, animal, etc., are to be obtained by preparing a rough outline with wires and then trainingthe shrub along the frame and clipping carefully over years to get the desired shape.

ACTIVITY/EXERCISE

1. Visit orchards situated in your area and try to find out which system of planting isbeing followed there. Compare the practices being followed in those orchards withmodern practices, which you have learnt in this chapter.

2. Plan a suitable scheme for an orchard, along with important fruits and their varieties,suitable intercrops, on 10 hectare of land in your region.

3. You can visit vegetable gardens of your locality and try to find out, which system ofvegetable growing is practiced, predominantly.

4. Choose some ornamental flowering plants like marigold or carnation and separatethem in two sets. Apply pinching and deshooting practice to two different sets ofplants, separately. Compare the size of flowers formed as a result of such practice.

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CHECK YOUR PROGRESS

1) Name the important systems for layout of fruit orchard. Explain each briefly.

2) What is high density planting? Cite some successful examples of HDP in fruit crops.

3) Write the most commonly followed spacing for different commercial fruit crops.

4) Enlist different methods of soil management practices in fruit crops.

5) Enlist different types of vegetable production system.

6) Name vegetable crops, which are usually transplanted in field for cultivation.

7) Differentiate between pinching and deshooting.

8) What do you mean by topiary?

9) How soil is sterilized to get rid off of fungi and other pests?

10) Name an ornamental crop, which is defoliated for improved flowering.

FILL IN THE BLANKS

1. Quincunx system of laying out orchard is also termed as…………………system.

2. Recommended spacing between two tamarind plants is…….m.

3. ……………………………….. is judicious removal of plant part to improve shape,influence growth, improve flowering, fruitfulness and fruit quality or to repair injuries.

4. Bahar is practiced in fruit crops like……………………… and… … … … … … … … … …

5. Vegetatively propagated vegetable crops are…….., ……………… and… … … … … … …

6. The purpose of mulching is to conserve …………………………

7. Pricking out is also known as ………….. out.

8. The removal of …………. is known as defoliation.

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Principles of Plant Propagation,Methods of Propagationfor Horticultural Crops

OBJECTIVES


• Gain knowledge of basic plant propagation techniques

• Gain a greater understanding of plant processes and lifecycles

• Develop skills in the art of budding and grafting

• Start agribusiness in nursery production of horticultural plants.

INTRODUCTION

Propagating new plants is both a science and an art. The study of it can provide a lifetimeof challenges and opportunities to learn more about this fascinating craft, or a basic knowledgeof it can provide the students with the skills and techniques to start their own business in nurseryproduction of horticultural plants since the demand for planting material of horticultural plantsis ever increasing. It can be of great fun to grow your own plants. You may already have someexperience growing different plants. Plant propagation is the multiplication of plants by bothsexual and asexual means. To start with, start growing a few tomato plants from seeding inkitchen garden, to the conservationist growing endangered species of orchids in test tubes, tothe commercial nurseries that grow the millions of annuals, perennials, bulbs, shrubs and treessold every year, a working knowledge of plant propagation makes all of these endeavors possible.This chapter will give the students greater confidence in producing plants from seed, cuttings,grafting, budding, layering and specialized vegetative structures along with essential skills towork in the horticulture industry.

What is Plant Propagation?

Plant Propagation is defined as the multiplication of plants by both sexual and asexualmeans.Propagation is an art of multiplication of plants. The horticultural plants are propagatedboth by sexual and asexual methods.

Most of the horticultural plants are now propagated through grafting and budding,fewthrough cuttings, layering, seeds and micro-propagation. The propagation methods are broadlyclassified as sexual,asexual and micro-propagation.

CHAPTER 4CHAPTER 4

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The details of methods are presented below:

Sexual Propagation

Sexual propagation is the raising of plantsby means of seed which is formed due to thefusion of male and female gametes within theovule of a flower. Plants that are produced fromseeds are called seedlings. In ancient times whenthe asexual methods of plant propagation werenot known, this was the only commercial methodfor plant propagation. Papaya, phalsa andmangosteen, vegetable crops and flowers are still being propagated by seed.

Advantages

• Seedling trees are generally long-lived, bear more heavily and all comparatively morehardy.

• This is the only means of reproduction, where asexual propagation is not possible oreconomical e.g. Papaya, phalsa, mangosteen etc.

• To develop new varieties, hybrids are first raised from seed and it is essential toemploy this method in such cases.

• It has been responsible for the production of chance seedlings of highly superiormerits.

• Polyembryonic character exists in many fruit plants such as in some citrus speciesand some mango varieties which give rise to more than one seedling from one seed.The nucellar seedlings are true to type. Therefore, polyembryomic varieties can bepropagated by seeds.

• Rootstocks upon which the fruit varieties are budded or grafted are mostly raisedfrom seeds.

• Seedlings are cheaper and easy to raise.

The study of plant propagation has three different aspects:

o A Knowledge of mechanical manipulations and technical skills- art of propagation.o A knowledge of plant growth and structures- science of propagation.o A knowledge of different kinds of plants and their methods of propagation

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• Easily transported to distant places e.g. seeds

• Does not require high technical knowledge and skilled labour.

Limitations/disadvantages

• Seedling trees are not uniform in their growth, yielding capacity and fruit quality.

• Seedling trees have long juvenile period and take more years to bear the first crop.

• Seedlings become large for economic management.

• It is not possible to maintain the exact character of any superior selection.

• Seed propagation can not be applied in many plants e.g. banana

• It is not possible to avail the modifying influence of rootstock on scion or scion onrootstock.

• Since seed-borne viruses exist in a number of fruit plants and the multiplication ofsuch plants by seed is not recommended.

Asexual propagation

Propagation of plants through any vegetative parts is called vegetative or asexualpropagation. The goal of vegetative propagation is to reproduce progeny plants identical ingenotypes to a single source plant.

Advantages:

• Vegetatively propagated plants are true to type, uniform in growth, yielding capacityand fruit quality.

• Vegetatively propagated plants come into bearing earlier.

• Uniformity in fruit quality makes harvesting and marketing easy.

• Modifying influence of rootstock on scion can be profitably availed off.

• It is possible to regulate the tree size, fruit quality, precocity etc. according to one'srequirements by using different rootstocks.

• Cross pollination can be effected by grafting shoots of other suitable varieties(pollinizers) on some of the branches of self-unfruitful variety.

• Grafting can be used to encourage healing of tree wounds caused by rodents,implements.

• Composite tree can be raised.

• One can correct to some extent the initial mistakes of planting inferior or unsuitablevarieties.

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• Fruit plants producing seedless fruits such as banana can only be multiplied throughvegetative means.

Limitations

• No new variety can be evolved by means of the vegetative method of propagation.

• Sometimes, it is more expensive.

• Vegetatively propagated plants are comparatively short lived.

Methods of Asexual Propagation:

Plant Propagation by Cutting: A portion of a stem, root or leaf is cut from the parentplant and is placed under certain favourable environmental conditions to form roots and shoots.Thus a new independent plant is produced which in most cases identical with the parentplant.

Stem-cuttings: Propagation by hardwood cuttings is simple and cheapest method ofmultiplication. Hardwood cuttings are easily handled and transplanted. One-year-old matureshoots are collected during November-February. Grape, fig, pomegranate,currant,gooseberry, some plums and apple are propagated by hardwood cuttings. Manydeciduous ornamental shrubs are started readily by this type of cuttings. Some commonones are privet, forsythia, wisteria, honeysuckle, willow, poplar, dogwood, Potentilla,Sambucus, and Spiraea. Rose rootstocks are propagated by hardwood cuttings.Weak andfast growing shoots with long internodes should not be used for this purpose. Length of

cuttings should be between 10 and 45cm. It should contain at least 2 buds. Just on the base ofshoot below the node a straight cut is given while on the top of the cutting, 1-2cm above the buda slanting cut is given. This helps maintain the polarity of the shoot and if rain occurs, waterdoes not accumulate on the tip of cutting.

Semi-hardwood cuttings are mostly used in evergreen fruit plants-mango, guava, lemonand jackfruit. Many broad-leaved evergreen shrubs such as Camellia, Pittosporum, Rhododendron,Euonymus, evergreen azaleas and holly are commonly propagated by semi-hard wood cuttings.The available shoots during June-July have not attained the full maturity and are 5-9 monthsold. Such shoots are used for propagation purpose. Length of cuttings should be 7-20cm. It isbetter to retain 2-4 leaves on the top of cuttings. Treating cuttings with 5,000ppm IBA givesbetter results.

Naphthelene Acetic Acid (NAA) and Indole-3-ButyricAcid (IBA) are the two most commonly used rootpromoting hormones used.

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A novel technique for rooting semi-hardwood cuttings has been perfected. It is knownas bottom heat technique. Semi-hardwood cuttings of mango, guava and aonla are preparedduring December and treated with IBA 5,000ppm. These cuttings are inserted in rootingmedium in a chamber maintained at 30±2°C, and 30-90% cuttings get established in thismethod.

Soft wood cuttings: Cuttings are prepared from the soft succulent new spring growth of specieswhich are 4 to 6 months old. Many ornamental woody plants can be propagated by softwoodcuttings. Typical examples are the hybrid French lilacs, Foresythia, Magnolia, Spiraea, maples.Nerium, crotons, Eranthemum, Graftophyllum etc can also be multiplied through this type ofcuttings.

Herbaceous stem cuttings: This type of cuttings is taken from succulent herbaceous green houseplants. For example, Chrysanthemum, Coleus, Carnations, Geraniums, Cactus and many foli-age plants are multiplied through herbaceous cuttings.

Softwood cuttings and herbaceous cuttings are not used to propagate fruit plants. Only2-3 months old shoot and very tender shoots are utilized.

Leaf Cuttings: Certain plants with thick and fleshy leaves have the capacity to produce plant-lets on their leaves. In leaf cuttings, the leaf blade with or without petiole and axillary bud isused for starting new plants. Adventitious roots and shoots form at the base of the leaf andform in to a new plant. However, the original leaf does not become a part of the new plant.Frequent watering and high humidity and bottom heating are desirable for better and rapidrooting of leaf cuttings. Sand or sand and peat moss (1: 1) are satisfactory rooting media forleaf cuttings. For leaf cuttings, depending on the species the whole leaf blade, leaf bladesections or the leaf with petiole is used. Begonia, African violets and peperomia are propa-gated by leaf cuttings.

Leaf-bud cutting: A leaf-bud cutting consists of a leafblade, petiole and a short piece of stem with attachedaxillary bud of actively growing leaf Black raspberry,blackberry, boysenberry, lemon, camellia, maple andrhododendron are readily propagated by leaf-budcuttings as well as many tropical shrubs and mostherbaceous greenhouse plants usually started by stemcuttings.

Root cuttings: As the name indicates, roots of the plant are utilized as propagating material.Roots 1 cm thick and 10-15cm tall are used. In temperate fruits, such kind of roots are prepared

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in December and kept in warm place in moss grass or wetsand for callusing and transplanted during February-Marchin open beds. Blackberry and raspberry are commerciallypropagated by this method. This method is also advocatedin pecan nut, apple, pear and peach.

Propagation by layering

Layering is the method of propagation in whichroots are developed on a stem while it is still attached to the parent plant. After properrooting, the stem is detached and becomes a new plant for growing on its own roots. Thehigh success of layering is obtained by ringing or wounding, etiolation (absence of light),use of rooting hormone (IBA, NAA) and favourable environmental condition (temperatureand humidity).

The layering can be natural means of propagation as in black raspberries and trailingblackberries or can be artificially created by different means. The layering techniques generallyemployed in fruit plants are:

Tip-layering: In tip-layering, rooting takes place near the tip of current season's shoot whichis bent to the ground. It is commonly followed in black berries, raspberries and dewberries.The stem of these plants complete their life in two years. During first year, vegetative growthtakes place while in the second year fruiting takes place. After harvesting plants are heavilypruned which give rise to number of lateral shoots. The tips of these shoots are buried 5-10 cmdeep in soil. Rooted layers are detached and planted in soil during spring.

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Serpentine layering: It is modification of simple layering in which one-year-old branch is alter-natively covered and exposed. The stem is girdled at its lower part. The exposed part of stemshould have at least one bud to develop a new shoot. After rooting, the sections are cut andplanted. Muscadine grape is commercially propagated by this method.

Air-layering: In this method, roots are formed in the aerial part of the plant. The stem is girdledand rooting hormone (IBA) is applied to upper part of cut. The moist rooting medium (mossgrass) is wrapped with the help of small polythene strip (200-300 gauze, transparent). This methodis commonly known as goottee. Many plants like litchi, kagzi lime, jackfruit, guava andcashewnut as well as Ficus species, Croton, Monstera and philodendron are propagated throughair-layering. February-March and June-July are the ideal periods for air-layering. Rooting in airlayers generally commences within 25-30 days and layers are ready for transplanting within 3months.

Buds above ground

Rooting from buried node

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Mound layering/stooling: In this method, the plant is headed back to 15cm above the groundlevel during dormant season. The new sprouts will arise within 2 months. These sprouts arethen girdled near base and rooting hormone (IBA), made in lanolin paste is applied to the upperportion of cut with moist soil. These shoots are left as such up to two days for proper absorptionof rooting hormone (IBA) before they are covered with moist soil. The concentration of rootinghormone varies from plant-to-plant but in general 3,000-5,000ppm is most commonly used. Therooting of shoots is observed within 20-30 days. After 2 months, the rooted shoots are separatedfrom mother plants and planted in nursery. Apple and pear root stocks and guava are commer-cially propagated by this method. However, this method is also advocated in other fruits likeplum, cherry, hazelnut, pecannut, mango, jackfruit and litchi.

Trench layering: Trench layering consists of growing a plant or branch of a plant in ahorizontal position in the base of trench and filling in soil around the new shoots. Roots aredeveloped at the base of new shoots, so produced. Rootstocks of apple, pear and walnut areusually propagated by trench layering.

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Plant propagation by grafting

Grafting is an art of joining parts of two independent plants in such a manner that theyunite and grow together into single independent plant. The part of graft combination which is tobecome the upper portion or the shoot system or top of the new plant is termed as scion and thepart which is to become the lower portion or the root system is the root stock or under stock orsome time stock.

Methods of grafting: There are two main types of grafting- attached scion methods ofgrafting and detached scion methods of grafting.In attached scion methods of grafting, the scionis still attached to the mother plant till the graft union takes place where as in detached scionmethods of grafting the scion is separated from the mother plant just before grafting. Inarchingor approach grafting is most important method under attached scion methods of grafting.

Inarching / Approach grafting: The distinguishing feature of this method of grafting is thattwo independent plants on their own roots (self sustaining) are grafted together. This methodprovides a means of establishing a successful union between certain plants which are difficult tograft by any other method as the two plants will be on their own roots till the formation ofsuccessful graft. Examples are Guava, mango, sapota.

Veneer grafting: This method of propagation holds promise for large scale commercialpropagation. The method is simple and can be adopted with success. Eight months to one yearold seedlings are used as rootstocks. In this method, a downward and inward 3-4 cm long cut is

In case of grafting, a bud stick consisting of two or more buds isinserted into the stock whereas in budding only single bud withor without wood is inserted into the stock.

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made in the smooth area of the stock at a height of about 20 cm. At the base of cut, a small shortercut is given to intersect the first so as to remove the piece of wood and bark. Proper selection andpreparation of scion are of utmost importance. The scion should be of matching thickness withthe stock, preferably a terminal non-flowered shoot of 3 to 4 months maturity. Remove the leafblades from the selected scion shoot on the mother plant keeping the petiole intact, about 7 to 10days prior to detaching. This helps in forcing the buds to swell and in increasing the graftingsuccess. The scion stick is given a long slanting cut on one side and a small short cut on the otherso as to match the cuts of the rootstock. The scion is inserted in the rootstock and the graft unionis then tied with polythene strip. The rootstock should be clipped in stages when the scion takesand remains green for more than 10 days.It is used widely for grafting plants such as Avocado,Mango etc.

Epicotyl (Stone) Grafting: This method of grafting is done on the epicotyl region of theyoung seedlings; hence the name epicotyl grafting. This method is simple, economical anduseful for multiplication of mango plants in large number in a less time. Fresh mango stones aresown in the nursery beds. Germinated seedlings of 10-15 days old with tender stems and copperyleaves are lifted along with stones. The roots and stones are dipped into 0.1 per cent Carbendazimsolution for 5 minutes after washing the soil. The seedling stems are headed back about 6-8 cmabove the stone. A vertical split (about 3-4.5 cm longitudinal cut) is made into the middle portionof the seedlings. A wedge shaped cut is given on the lower side of scion. The scions should be 4-5 months old and 10-15 cm long containing plumpy terminal buds. The scion is then inserted inthe cleft of the seedlings and tied with polythene tape. Immediately thereafter, the grafts areplanted in polybags filled with the mixture of soil and farmyard manure (1:1). The polybags arewatered and then kept in the shade protecting from sun and heavy rain. The successful grafts

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should be shifted to open space or may be planted in nursery beds when their leaves becomegreen. The most suitable time for stone grafting is July. Examples are Cashew, mango etc.

Soft wood grafting: This method is similar to that of cleft or wedge grafting. In the past,this technique has been used for in situ orchard establishment under dry land conditions as thegrafting operation is performed using cleft/wedge method on the newly grown top portion ofthe plant one year after the establishment of rootstock in the field. In this method, 3 to 8 monthsold seedlings are used as rootstocks. The scion shoots of the thickness equal to that of rootstocksare defoliated 7-10 days prior to grafting. The graft should be secured firmly using 1.5 cmwide, 150-gauge polythene strip. The best time for the success of softwood grafting is July andAugust.

Cleft grafting: This method is employed in the nursery when the rootstock is quite thickerthan the scion. It can be done successfully in the rootstock having a diameter of 3-10 cm. Avertical split (5 cm) is made in the rootstock with a sharp knife. The scion should be one year old,about 15-20 cm long and having 3-4 buds above theslanting cuts. For preparing the scion, two slanting cuts(5-6 cm) each are given on the opposite sides. The scionis inserted into the split of the rootstock in such a waythat the cambium of both stock and scion coincides.Careful tying is necessary to avoid displacing the scionand separating the cambiums. The graft union is then tiedwith the help of 150 gauge polythene strip. Sprouting ofscion shoots starts within 3 weeks of grafting. Thepolythene strip is removed after about 6-8 weeks ofgrafting. The sprouts arising below the graft union shouldbe removed periodically. The best time for cleft graftingis December- February in temperate fruits.

Steps in cleft grafting

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Tongue Grafting

This method is highly effective and widely employed for the propagation of peachand pear. In this method, the diameter of the scion and the rootstock should be equal. In thismethod, a flat slanting cut, about 5 cm long is given at the base of the scion so that the lowest budis about midway along the cut but on the opposite side. A downward pointing tongue is madein the upper half of the slanting surface. A slanting cut, corresponding in length to that of thescion, is made upwards through the stock 15-20 cm above the ground. An upward pointingtongue is made in the upper half of this slanting surface. Thecut surfaces of the scion and stock are now placed together sothat the tongues interlock and the cambial regions are in closecontact. This interlocking of tongue gives greater surface forthe root stock and scion come into contact with each other tomake the strong union. Careful tying is necessary to avoiddisplacing the scion and separating the cambiums. The graftunion is then tied with the help of 150 gauge polythene strip.Sprouting of scion shoots starts within 3 weeks of grafting. Theperiodical removal of sprouts below the graft union should becarried out. The polythene strip is removed after about 6-8weeks of grafting. Examples are apple, pear, peach, plum,apricot, almond, cherry, kiwi fruit, pecan nut etc.The best timefor tongue grafting is December- Februaryin temperate fruits.

Plant Propagation by Budding

Budding is also a method of grafting wherein only one bud with a piece of bark and with orwithout wood is used as the scion material. It is also called as bud grafting. The plant that growsafter union of the stock and bud is known as budding.

Methods of budding:

T-Budding (Shield budding): This method is known as T-budding as the cuts given on thestock are of the shape of the letter T, and shield budding as the bud piece like a shield. Thismethod is widely used for propagating fruit trees and many ornamental plants. This method isgenerally limited to the stock that is about 0.75 to 2.50cm in diameter and actively growing sothat the bark separate readily from the wood. Example is Rose and Citrus.

Steps in Tongue grafting

Generally grafting is performed during dormant season whereasbudding is done during active growing season

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Inverted T- Budding: In heavy rainfall areas, waterrunning down the stem of the stock may enter the T cut,soak under the bark and prevent healing of the bud piece.Under such conditions, an inverted T budding may givebetter results as it is more likely to shed excess water.Inverted T budding procedure is same as that of T-budding except the horizontal cut on the stock is madeat the bottom of the vertical cut rather than at the top.

Patch Budding: In this method a regular patch ofbark is completely removed from the stock plant andis replaced with a patch of bark of the same sizecontaining a bud from the desired mother plant. Forthis method to be successful the bark of the stock andbud stick should be easily slipping .The diameter of thestock and bud stick should be preferably by about thesame (1.5 to 2.75cm). Examples are Pecan nut and walnut. Steps in patch budding

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Ring budding: The bud is prepared by taking a ring of a bark, 3cm long with the bud in thecentre. In the root stock, two transverse cut 1.5cm apart are made and these are connected with avertical cut and a ring of bark is removed. The prepared scion bud with the ring of bark is fittedin the exposed portion of the rootstock and tied. Example is ber.

Double working: It is practiced for several purposes (i) to over come incompatibilitybetween the stock and scion. Incompatible stock and scion may be united by means of a piece ofinterstock that is compatible to both (ii) to secure resistance to drought or cold by providing adisease or cold resistant trunk by means of double working. (iii) To obtain resistance to pest anddwarfing effect by using a pest resistant stock and a dwarfing stock and (iv) top working ofgrafted orchard trees is essentially a double working; here the tree trunk as an intermediatestock may exert certain influences on the new top.

Top working: Top-working for changing a variety is generally done on long lived species,growing in a healthy condition. Short lived species, old trees or diseased trees are not suitablefor top working; in such cases new planting is considered more economical and useful than topworking.

Micro-propagation

Micro propagation (tissue culture or invitro culture) refers to the multiplication of plants,in aseptic condition and in artificial growth medium from plant parts like meristem tip, callus,embryos anthers, axillary buds etc. It is a method by which a true to type and disease free entireplant can be regenerated from a miniature piece of plant in aseptic condition in artificial growingmedium rapidly throughout the year. This method is gaining popularity because of advantagesover other conventional methods.

Advantages

• Large-scale multiplication in lesser time and space

• Production of virus-free plants

• Year-round production of plants

• Highly beneficial in those fruits where vegetative propagation is difficult

• In dioecious fruit plants, production of female plants is possible through micro-propagation. Papaya, is a good example.

Under micro-propagation, different plant parts are cultured. Based on explant, differentin-vitro methods are used for propagating fruit plants. They are shoot-tip culture, meristem-tipculture, embryo culture and ovule culture.

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Tissue culture technique has been perfected in banana. Shoot tips excised from rhizomesof sword suckers are suitable explants and MS medium supplemented with sucrose (3%), andgelite (0.25%) is the best. Shoot tips and micro-cuttings are highly suitable explants for faster anddisease-free production of grape. Salt-tolerant rootstock of grape has increasing demand and in-vitro propagation has been successfully used. Seed-propagated papaya often shows highvariability, undesired ratio of male and female plants. Shoot tip culture technique has beensuccessfully used in producing female plants in papaya.

Micro-propagation has been referred to as the most ideal method for propagation ofstrawberry and blackberry. Scientists in India and abroad are trying hard to perfect micro-propagation in mango, coconut, litchi. However, the success is limited.

Micro-propagation, however, has its limitations. The facilities required are very costly. Itrequires technical skill, pathogen/disease if appeared in culture may be multiplied to very highlevels in a short time and establishment of laboratory produced plants in field is a difficult taskuntil properly hardened.

APOMOXIS

The embryo is generally produced by sexual reproduction but there are certain cases inwhich the embryo is produced by an asexual process. This is of great value as the resulting plantcan be reproduced by seed propagation in almost the same manner as it would be by any othervegetative method. The seedlings produced through apomixes are known as apomictic seedlings.Apomictic seedlings are identical to their mother plants and similar to the plants raised throughother vegetative means, as it has the same genetic make-up as that of the mother plant. Hence,propagation by means of apomictic seedlings is equivalent to vegetative propagation. Thephenomenon in which an asexual reproductive process occurs in place of the normal sexualreproductive process of reduction division and fertilization is known as apomixis.

Kinds of apomixis:

Obligate apomixis: Plants that produce only apomictic embryos are known as obligateapomicts.

Facultative apomixis: Plants that produce both apomictic and sexual seedlings are calledfacultative apomicts.

Types of apomixis:

Recurrent apomixis: In this the embryo develops from the diploid egg cell (diploidparthenogenesis) or from some other diploid cells of the embryo sac, with out fertilization (diploid

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apogamy). As a result, the egg has the normal diploid number of chromosomes, as in the motherplant. e.g, Onion, raspberry, Apple etc. In some plants apomixis occurs without the stimulus ofpollination, in others pollination is necessary for embryo development.

Non-recurrent apomixis: In this type, the embryo develops directly, either from the haploidegg cell (haploid parthenogenesis) or some other haploid cells of the embryo sac (haploidapogamy). In this case haploid plants are always produced. As the plants produced by thismethod contain only one set of chromosomes, these are sterile and the process is not continuedfor more than one generation. Non-recurrent apomixes does not commonly occur and is primarilyof genetic interest. e.g. Solanum nigrum, Lilium spp.,etc.

Adventitious apomixis (Adventitious embryony or nucellarembryony): In this type ofapomixis the embryo does not develop from the cells of the embryo sac, but develops from anydiploid sporophyticcell, eg.,cells of the nucellus (usually), integument etc. Hence, the diploidcells of the sporophyte giverise directly to diploid new embryos. This type of apomixis is foundin citrus, where fertilization takes place normally and a sexual plus a number of apomictic(nucellar) embryos develop. In opuntia also this type of apomixis occurs.

Vegetative apomixis (Bulbils): In this case the flowers in an inflorescence are replaced bybulbils or vegetative buds, which often sprout into new plants while they are still on the motherplant. This type of apomixis is found in some species of Allium, Agave, Diascorea, Pao etc.

Poly embryony: This is a type of apomixis.The phenomenon in which two or more embryospresent with in a single seed is called polyembryony. When such seeds are sown, more than oneseedling arises from the seed. Of them one is from the zygote (Sexual seedling).The others areasexual or apomictic seedlings. The reasons for this phenomenon are many. The origin of theseextra embryos or seedlings varies.

a) From nucellus-Nucellarmbryony as in citrus and mango

b) From seed coats (integuments) or antipodals or synergids -rare-mango.

c) Occasionally more than one nucleus develops with in the embryo sac (in addition tothe usual and regular nucleus).

d) Cleavage of the embryo during the early stages of development is common occurrence.

What ever may be the place of origin, the common thing is, these embryos arise from thematernal tissue of the plant. Example are Citrus, Mango, Jamun, Rose, apple etc. The polyembryonic seedlings are uniform and true to parent like other vegetatively propagated plants.They are derived by mitosis, and come from maternal tissue (not by meiosis), but they have thecharacteristics of sexual seedlings like juvenility, vigour, freedom from virus diseases. Examplesare Citrus, Mango, Jamun, Rose apple.

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How to differentiate the poly embryonic and sexual seedlings: It is difficult to differentiatein the nursery. Generally more vigorous seedlings are considered to be polyembryonic. Byrejecting about 10% of weaker and weakest seedlings, one can have fairly uniform poly embryonicseedlings.

Standardized and commercial methods of propagation in fruits

Name of fruits Methods of propagation

Standardization Commercial

Acid lime Seed, budding, air layering Seed

Avocado Grafting (cleft, side, whip), Layering, T-buddingchip budding and cutting

Aonla Budding (patch, shield) Patch budding

Bael Root cutting, budding, (Patch Patch buddingand Shield), air layering

Ber Cutting, air layering, budding, Ring and T-budding(T, I, ring and forkert)

Carambola Seed, approach grafting Seed

Custard apple Soft wood grafting T-budding, Inarching, Offshoots

Date palm Seed, Offshoots Offshoots

Fig Cutting, budding and air layering Hard wood cuttings

Grape Hard wood stem cutting, chip Hard wood stem cuttingsbudding, layering andmicropropagation

Grapefruit Seed and budding (patch, shield) T-budding

Guava Cutting, air layering and budding Stooling, Inarching

Jamun Seed and budding Shield and Patch budding

Karonda Seeds, soft wood stem Seeds, Air layeringcuttings in mist

Lemon Seed and layering Air layering, hard woodstem cuttings

Litchi Air layering, splice grafting, Air layeringbudding

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Longan Seeds, inarching, tongue Air layeringgrafting, air layering

Loquat Budding, grafting, seed Inarchingand air layering

Mandarin Seeds and budding T/shield budding

Mango Inarching, side and Veneer Inarching, Veneer graftinggrafting, budding, stool layeringand cutting, cleft grafting

Passion fruit Stem cutting, cleft grafting Seeds

Persimmon Grafting and budding` Crown grafting

Phalsa Seeds and cutting Seeds

Pomegranate Budding (chip, patch and forkert), Hardwood stem cuttingsair layering, inarching and Air layering

Pummelo Seed and budding Seed, T-budding

Sweet orange Seed and budding T-budding

Propagation by specialized vegetative structures

Some fruit plants have natural structures-runner, sucker, offset, rhizome and crown-forpropagation.

Runner: It is a specialized stem which is producedfrom the leaf axil at the crown of plant and prostratehorizontally. The roots appear at one of the nodes havingcontact with soil. After root formation in the new plant, thecontact with the mother plant is automatically detached andnew plant can be separated and planted. Strawberry is thetypical example which is commercially propagatedthrough runners.

Suckers: A sucker is a shoot which arises on a plant below theground. However, in practice, shoots which arise from vicinity of thecrown are also referred to as suckers. Pineapple is usually propagatedthrough suckers. In banana, 2 types of suckers are produced-watersucker and sword sucker. Water suckers are broad leaved while swordsuckers are pointed and in the shape of a sword.

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For propagation purpose, sword suckers are preferred over water suckers.

Offset: It is a lateral shoot or branch which is developed from base of the main stem. Thedate palm and pineapple produce such type of lateral shoots by which they can be propagated.

Plant propagation by division: It is a method of propagation of plants using cut section ofa particular part like rhizome, tuber and tuberous root etc.

Rhizome: A rhizome is a modified stem structure in which the main axis of the plant growshorizontally just below or on the surface of the ground. Banana is a typical example whererhizome is cut into pieces in such a way so that each piece contains at least 3 lateral buds (eyes)for propagation.

Ginger rhizome Turmeric rhizomes

Crown: It designates that part of a plant at the surface of ground from which new shoots areproduced. In strawberry plant, where leaves are seen in groups, is offenly referred to as 'crown'of plant. Similarly, at the top is the crown of pineapple plant, which can be used for propagationpurpose.

Corm: The bulb consists predominantly of modified leaves; the corm is a modified stem.Food is stored in this compact stem, which has nodes and very short internodes and is wrappedup in dry, scaly leaves. When a corm sprouts into a new shoot, the old corm becomes exhaustedof its stored food and is destroyed as a new corm forms above it. Several small corms, or cormels,arise at the base of the new corm. The cormels may be separated from the mother corm at maturity(die back) and used to propagate new plants. e.g. Amorphophallus, Colocasia, Gladiolus etc.

Gladiolus corm(Source: Plant facts Ohio state university)

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Stolon: It is a term used to describe various types of horizontally growing stems thatproduce adventious roots when come in contact with the soil. These may be prostate or sprawlingstems growing above ground. In propagating plants by stolon, the stolon can be treated as anaturally occurring rooted layer and can be cut from the parent plant and planted separately.For example, Mint, Bermuda grass etc.

Stem tuber: A tuber is specialized swollen underground stem which possesses eyes inregular order over the surface. The eyes represent the nodes of the tuber. The arrangement of thenodes is spiral, beginning with the terminal bud on the stolon to produce a new plant, the tuberis divided into sections so that each section has a good amount of stored food and a bud or eye.Propagation by tubers can be done either by planting the tubers whole or by cutting them intosection, each containing a bud or eye. For example, Potato.

Stem tuber of Potato

Root tuber of Sweet potato

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Tuberous roots: These are thickened tuberous growth that functions as storage organs.These differ from the true stem tuber, in that they lack nodes and internodes. Buds are presentonly at the crown or stem end. Fibrous roots are commonly produced towards the opposite end.Most plants with fleshy roots must be propagated by dividing the crown so that each sectionbears a shoot bud. For example, Dahlia, Begonia, Sweet potato.

Offset: It is a short thickened horizontal branch growing out of the crown ending at theapex with a tuft of leaves and a cluster of leaves below. These are special type of branches orlateral shoots which are produced from the base of main stem of parent plant. The offset oftenbreaks away from the mother plant and the daughter starts a new independent life. Forexample,Pistia, Agave, Water hyacinth, Cycas, Dracaena etc.

Propagation by seed

Papaya, phalsa, kagzi lime and jamun are usually propagated by seeds. Seeds are alsoused to raise rootstock seedlings in many fruit crops such as citrus and mango. This methodbeing the easiest and cheapest is generally employed on a commercial scale in the fruit crops. Inmango and citrus, nucellar seedlings can be used to raise true-to-type plants. Seed propagationis essential for breeding new plant type, conserving gene pools. Propagation by seed requires athorough knowledge of seed viability, its storage, time of sowing, factors responsible forgermination and care of germinated seedling is essential.

The condition in which the seed can germinate immediately upon the absorption of waterin the absence of any internal germination barrier, the embryo (or seed) is said to be quiescent.While those seeds which fail to germinate even though the embryo is alive, moisture is absorbedand favourable condition are provided are known as dormant seeds.

In most of the fruit crops, there may be natural or chemical dormancy. The dormancy inseeds of ber, guava and walnut is due to presence of hard seed coat which inhibits penetration ofwater and oxygen required for germination. Presence of chemical inhibitors (abscisic acid) isresponsible for dormancy in seeds of most of temperate fruits (apple, pear, peach and walnut).Besides ABA, higher concentration of pectin, gum, tannin and amino acids (trypophan) are alsoresponsible for dormancy in seeds of temperate fruits.

How to overcome dormancy

Seed dormancy due to hard seed coat can be overcome by softening the seed coat and othercovering. It can easily be done either by scarification, stratification or by use of chemicals andhormones.

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Scarification: It is the process of breaking, scratching, altering or softening the seed coveringto make it permeable to water and gases. Scarification can be achieved mechanically, or by hotwater and acid.

In mechanical scarification, cracking of seed with hammer, rubbing with sand paper orcutting with a file without injury to embryo is generally employed to break the dormancy (ber,peach and walnut).

Impermeable seed coat of guava can be softened by hot water scarification. Seeds are placedin hot water at 77°-100°C. They are immediately removed from hot water and allowed to soakgradually in cool water for 12-24hr.

Acid scarification consists of treating guava seeds with concentrated sulphuric acid for 3minutes, ber for 5-6 hr and strawberry seeds with 0.25% nitric acid or hydrogen peroxide resultsin higher germination.

Stratification: It is the method of handling of dormant seeds, in which, the imbibedseeds are subjected to a period of chilling to after-ripen the embryo. This term originated asthe nurserymen used to place seeds in stratified layers interspaced with a moist mediumsuch as soil or sand out of door or in pits during winter. The term moist chilling has beenused as synonym to stratification. Stratification can be achieved by refrigeration of dormantseed.

Dormant seeds of temperate fruits like apple, cherry, pear and apricot are generally placedin layers of sand in a box at a temperature of 1°-5°C. Depending upon the seed type, treatmenttime varies from 1-5 months for breaking dormancy of seeds.

The seed dormancy due to presence of growth inhibitors can be broken by placing theseeds in running water. It results in leaching of inhibitors. The freshly extracted seeds of strawberryand grape if placed in running water for 7-12 days result in increased germination.

Chemical treatments: Many freshly harvested dormant seeds usually respond to soakingin potassium nitrate solution. This technique is largely used in seed testing laboratorieswhere seeds are placed in petri-dishes containing 0.2% solution of potassium nitrate. Theseeds of peach and grape, treated with 5,000ppm of thiourea show enhancement in theirgermination.

Use of hormones: The seed dormancy can also be overcome by the treatment of growthregulators. Treatment of seeds of apple, cherry, peach, strawberry and hazelnut with 100-500ppmof GA3 for 24-48hr improves germination and better growth of seedlings. Ethrel (5,000ppm)-treated seeds of guava and strawberry also show better germination and growth of seedlings.

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Treatment of apple and peach seeds with 10-20ppm solution of benzyle adenine (BA) is effectivefor higher seed germination.

Seed sowing

The fruit seeds are sown in seed bed, polythene bags or in situ. Seeds of tropical andsubtropical fruits are sown during monsoon (June-July) or in the beginning of spring (February-March). Generally seeds of mango and jackfruit are sown during June-July while those of guava,ber and aonla during February-March. Seeds of temperate fruits are generally available duringJune-October and their sowing should be done after the dormancy period is over. In citrus,mango, loquat, litchi and jackfruit, seed viability is very less, so these should be sown immediatelyafter extraction. In north India, seeds of different citrus types are available during winter months.Germination of seeds is low due to prevailing low temperature. Hence use of polythene sheeton seed beds during December-January is useful in increasing germination percentage and fastergrowth of seedlings.

The seeds are usually sown at a depth 3-4 times of their size. It should be a little deep inlight soils while shallow in heavy soils.

Nowadays, sowing of seeds in polythene bags, earthen pots and pans is becoming popular.It is usual practice to sow papaya seeds in polythene bags. For epicotyl grafting, mango stonesare also sown in polythene bags.

While raising the plants in polythene bags, care should be taken that root system developsproperly. It has been observed a number of times that the roots get twisted and there is difficultyin establishment of the plants in field due to poor anchorage.

In-situ sowing: In walnut, pecan nut, jackfruit and ber, the tap-root system is very vigorous.So during the process of transplanting, root system is disturbed which ultimately affects theirestablishment in the field. Therefore, for these fruits, sowing of seeds in-situ is recommended. Inrocky soils, in-situ sowing of mango seeds and grafting later on is recommended.

Seed storage: Based on storage behaviour, seeds are classified as orthodox or recalcitrant.The orthodox seeds can tolerate loss of moisture and their longevity can be increased by preservingthem at low temperature. These include the seeds of apple, ber, custard-apple, date palm, fig,grape, guava, lemon, lime, mandarin, mulberry, papaya, passion fruit, peach, pineapple, plum,phalsa, pomegranate and sweet orange. Recalcitrant seeds do not withstand desiccation andneed a critical level of moisture to survive. Such seeds can be stored for relatively short periodranging from a few weeks to a few months. Seeds of fruits which show recalcitrant behaviour areavocado, barbados cherry, carambola, breadfruit, durian, jackfruit, litchi, mango, mangosteen

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and rambutan. Seeds of most of the tropical and subtropical fruits cannot be stored for a longperiod. However in controlled temperature and humidity, storage period can be prolonged.

Cryopreservation: It is the method of storage of material in liquid nitrogen maintained at atemperature of -196°C. Successful cryopreservation of material involves the application ofchemicals known as cryoprotectants. The most commonly used chemicals are glycerol and DMSO(Dimethyl sulphoxide). This method has recently been used in preservation of embryos of coconutand jackfruits under in-vitro systems.

ACTIVITY/EXERCISE

1. Describe and explain the conditions needed for successful plant propagation fromstem and leaf cuttings

2. Make three different types of stem cuttings.

3. Demonstrate knowledge of propagating plants by layering/grafting/budding in fruitplants growing in your farm/nearby orchard.

4. Visit nearby fruit/flower nursery and find out the methods of propagation beingused by nurserymen for the multiplication of various fruits and flowers.

CHECK YOUR PROGRESS

1) Define asexual propagation. How does it differ from sexual propagation?

2) Asexual propagation is advantageous in horticulture, why? Also write its limitations.

3) Enlist different types of layering and describe air layering giving suitable examples.

4) Differentiate between the followings:

a. Grafting and budding

b. Softwood and herbaceous cuttings

c. Leaf cuttings and leaf bud cuttings

d. Stratification and scarification

e. Mound layering and trench layering

5) How seed dormancy can be overcome?

FILL IN THE BLANKS

1. Two most commonly used rooting hormones are ……………and ………………

2. Strawberry is commercially propagated through ………………..

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3. Grafting is generally performed during……………..season and buddingduring………………season.

4. Seed germination can be improved by the application of ………………growthregulators.

5. Inverted T budding is generally done in areas experiencing…………….rains.


Bose, T.K., Mitra, S.K., Sadhu, M.K. and Das, P. 2001. Propagation of Tropical and

Sutropical Crops. NayaProkash Publishers, Calcutta.

Chadha, K.L. 2001. Handbook of Horticulture. Indian Council of Agricultural Research. NewDelhi.

Chattopadhyay, T.K. 1999. A Text Book of Pomology. Vol. I-IV. Kalyani Publishers, Ludhiana.

Gill, S.S., Bal, J.S. and Sandhu, A.S. 1985. Raising Fruit Nursery. Kalyani Publishers, Ludhiana.

Hartmann, H.T., Kester, D.E.and Davies, F.T. 1993. Plant Propagation. Prentice Hall of India Pvt.Limited, New Delhi.

Kunte, Y.N., Kawthalkar, M.P.andYawalkar, K.S. 2005. Principles of Horticulture and FruitGrowing. Agri-Horticultural Publishing House, Nagpur.

Sharma, R.R. 2002. Propagation of Horticultural Crops (Principles and practices).

Kalyani Publishers, Ludhiana.

http://www.iihr.ernet.in


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Essential Plant Nutrients, Their DeficiencySymptoms and Toxicities

in Horticultural CropsOBJECTIVES

After studying this chapter, the students should be able to learn about:

• Essentiality of plant nutrition

• Classification of essential nutrients on the basis of their requirement to plant

• Identify and diagnose common plant nutrient deficiency andtoxicity symptoms

INTRODUCTION

Plants, like all other living things, need food for their growth and development.The plantnutrients are essential for optimum plant growth. Nutrients are naturally present in the soil.Now, certain questions may arise in your mind. Why does plant need nutrients? How manynutrients are required for the growth and development of the crop? What are their functions andeffects on plant growth and development? What will happen if there is deficiency of thesenutrients? How will we identify and diagnose the deficiency symptoms of a particular nutrientin the soil? You can face several questions of this category. Each nutrient assists with differentplant functions that allow the plant to grow and reproduce. Each plant nutrient is needed indifferent amounts by the plant, and varies in how mobile it is within the plant. It is useful toknow the relative amounts of each nutrient that is needed by a crop in making fertilizerrecommendations. In addition, understanding plant functions and mobility within the plantshould prove useful in diagnosing nutrient deficiencies. The knowledge of the specific role ofthe essential elements in normal growth and development of the plant, their deficiency symptomsand amount required for the optimum crop production is considered necessary to understandsoil fertility better and to adopt scientific use of fertilizers. Plant nutrients taken up by cropsduring the growing season may come from many sources including soil, synthetic fertilizers ormanure, and also crop residues. Most soil conditions across the world can provide plants withadequate nutrition and do not require fertilizer for a complete life cycle. However, man canartificially modify soil through the addition of manures and fertilizer to promote vigorous growthand increase yield. It is essential to apply balanced quantity of nutrients through man-madefertilizers. An element present at a low level may cause deficiency symptoms, while the sameelement at a higher level may cause toxicity.

CHAPTER 5CHAPTER 5

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What is Plant nutrition?

Plant Nutrition is the study of the chemical elements and compounds that are necessary forplant growth, and also of their external supply and internal metabolism.During the first half ofthe 19th century, it was found that element are absorbed by roots principally as inorganic ions insoils and these are derived mostly from mineral constituent of soil. The term Mineral Nutritiongenerally refers to an inorganic ion obtained from soil and required for plant growth.

The process of absorption,translocation and assimilation of nutrientsby the plants is known as mineralnutrition. Nutrients are chemical elements,which are absorbed by the plants in moreand less large quantities to transform lightenergy into chemical energy and to keepup plant metabolism for the synthesis oforganic materials.

Criteria of Essentiality:

Arnon& Stout proposed criteria of essentiality, which was refined by Arnon (1954).According to this criterion, an element is considered as essential when-

1. A deficiency of the element makes it impossible for the plant to complete its life cycle.

2. Its deficiency can be corrected or prevented only by supplying this element.

3. The element is directly involved in the metabolism of the plant.

Essential Nutrients: An essential nutrient is one required by an organism for normal growthand development, but which it cannot manufacture on its own. There are 17 elements which areessential for plants namely, carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus(P),potassium(K), calcium(Ca), magnesium(Mg),sulphur(S), Iron(Fe), manganese(Mn), zinc(Zn),copper(Cu), molybdenum(Mo), chlorine (Cl), boron (B) and Nickel (Ni) . Ni is recently added asan essential nutrient. There is a dispute among plant physiologists concerning the role of nickelin plant nutrition. Since many physiologists exclude it as essential, in some textbooks, lists consistof only 16 essential inorganic nutrients.

Classification of essential elements: Over 95 percent of the dry weight of a flowering plantis made up of three elements namely, carbon, hydrogen, and oxygen which are taken by theplant from the air and water. The remaining 5 percent of the dry weight comes from chemicals

Difference between plant nutrition andfertilization

Plant nutrition means need for basic chemicalelements for plant growth whereas fertilizationrefers to the external application of syntheticplant nutrients to supplement the nutrientsnaturally present in the soil.

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absorbed from the soil. Roots absorb the chemicals present in their surroundings, but only 14 ofthe elements absorbed are essential for plant growth. These 14 elements, along with carbon,hydrogen, and oxygen, are called the 17 essential inorganic nutrients, or elements. All elementsare needed in specific amounts.

Therefore, depending upon the quantity of nutrients present in plants, these elements canbe grouped into three categories:

1. Basic Nutrients- Of the 95% of total dry matter of plants, carbon and oxygen constitute45% each. Example:- total dry matter produced by rice crop in one season is about 12t/ha in which 5.4 t is oxygen, 5.4 t is carbon and 0.7 t is hydrogen.

2. Macronutrients - The nutrients which are required in larger quantities for better growthand development of the plant are known as macronutrients. They include N, P, K, Ca,Mg, and S. Among these, N, P and K are called primary nutrients whereas Ca, Mg,and S are known as secondary nutrients. They are known as secondary nutrients dueto their secondary importance to the manufacturer of primary nutrient fertilizers.

3. Micronutrients- The nutrients which are required in small quantities are known asmicronutrients or trace elements. They are Fe, Zn, Cu, B, Mo, Mn and Cl. These arealso known as trace/minor/rare elements which are very efficient. Their deficiencyand excess can be harmful to the plants.

Plants use elements in differingamounts and forms e.g. some as cationsand others as anions. Almost all elementsare used in a variety of ways-

1. Catalysts for enzymaticreactions (either as part of theenzyme structure or asregulators or activators),

2. Regulators of the movement of water in or out of the cell and maintenance of turgorpressure

3. Regulators of membrane permeability,

4. Structural components of the cell or of electron receptors in the electron transportsystem, or as buffers (which maintain the pH within cells).

NON-MINERAL NUTRIENTSThree elements, carbon (C), hydrogen(H), and oxygen (O), are considered to be non-mineral nutrients because they are derived fromair and water, rather than from soil minerals.Although they represent approximately 95% ofplant biomass, they are generally given littleattention in plant nutrition because they arealways in sufficint supply.

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Based on the functions, the nutrients are classified into four groups:

1. Elements that provide basic structure to the plant- C, H, O.

2. Elements useful in energy storage, transfer and bonding- N, S, P. These are accessorystructural elements which are more active and vital for living tissues.

3. Elements necessary for charge balance- K, Ca, Mg. These elements act as regulatorand carriers.

4. Elements involved in enzymes activation and electron transport- Fe, Mn, Zn, Cu, B,Mn, Cl. These elements are catalyzers and activators.

The importance of all the 17 essential elements lies in their specific function or roles invarious biochemical or biological system essential for growth and development of plant. Aseach nutrient perform specific function, its adequate and deficient supply lead to developmentof visual deficiency symptoms in plants. The deficiency symptoms generally appear on specificplant parts i.e leaves, stem or roots. Deficiency symptoms are the first indication of nonavailability of nutrients in soil and hence the specific and general functions and visual deficiencysymptoms of the essential plant nutrients will help in better understanding of fertilizer ornutrient need of plants. The major functions and deficiency symptoms of essential plant nutrientsare as under:

Functions, deficiency symptoms and toxicities of essential plant nutrients:

Carbon, hydrogen and oxygen: These are the major constituents of organic compoundslike carbohydrates and fats found in the plants and provide energy required for growth anddevelopment. They are rarely limiting as a nutrient and there are no specific symptoms

Nitrogen

It is a constituent of proteins, enzymes, vitamins and plant hormones. It imparts vigorous

Mobile nutrients are nutrients thatare able to move out of older leavesto younger plant parts whensupplies are inadequate. Mobilenutrients include N, P, K, Cl, Mg,and molybdenum (Mo). Becausethese nutrients are mobile, visualdeficiencies will first occur in theolder or lower leaves and effects canbe either localized or generalized.

Immobile nutrients(B, Ca,Cu, Fe, Mn, Ni, S,and Zn) are not able tomove from one plantpart to another and deficiency symptoms willinitially occurin the younger or upper leavesand be localized. Zn is a partial exception tothis as it is only somewhat immobile in theplant, causing Zn deficiency symptoms toinitially appear on middle leaves and thenaffect both older and younger leaves as thedeficiency develops.

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vegetative growth and dark green colour to plants, produces earlygrowth, delays maturity of plants, and governs the utilization ofpotassium, phosphorus and other elements. Its deficiency results indrastic reduction in vegetative growth, stunted shoots and roots withthin, upright and spindly appearance. Chlorosis is first observed on olderleaves. Leaves are thin, fragile, small, pale- yellowish in colour anddefoliate prematurely. Flowering, fruit-bud formation and fruit settingare reduced. Woody fruits without any flavour are formed. Excess levelsresult in abundant foliage with dark green colour, making plants moresusceptible to pest and disease attack. Yields are low. Fruits are poorlycoloured with poor eating quality and storage properties. It delays fruit maturity. P uptakeis low.

Phosphorus

It is found in younger parts-flowers, maturing fruits and seeds. Itenhances maturity of crop, root growth and development, activity ofrhizobia and formation of root nodules. Its deficiency leads to stuntedroots and shoots with abnormally small leaves with dull dark greencolour, which later turns into bronze colour. Older leaves prematurely defoliate. Flowering isdelayed, fruit-bud formation is reduced, and yields are with poor quality. Excess of P resultsin interveinal chlorosis in younger leaves and marginal scorch of older leaves followed bynecrosis, tip die back, heavy leaf shedding and death of shoots. It results in Zn, Cu, Mn and Fedeficiency.

Potassium

Young leaves, root tips and meristematic tissues are very richin K. It is involved in cell division, synthesis and translocation ofcarbohydrates and synthesis of proteins in meristematic tissues. Kplays a unique role in osmotic regulation, opening and closing ofstomata. It has a beneficial effect on symbiotic N2 fixation byleguminous plants and increases resistance of plants to variousabiotic and biotic stresses. It improves the colour, flavour and size offruits. Deficiency symptoms first appear on recently matured leaves. Marginal burning of leavesstarts from tip which turns reddish-brown in colour and eventually die giving a scorched, raggedappearance. Shoots are thin with poor growth. Excess of K leads to Mg, Mn, Zn and Fe deficiencyby affecting their uptake.

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Calcium

Calcium occurs mainly in the leaves as calcium pectate. It plays an important role in celldivision, elongation, maintenance of membrane integrity, development and functioning of rootsand root apices, respiration, uptake of N, Fe, B, Zn, Cu and Mn. Since Ca is not freely mobile, itsdeficiency first appears on the shoot tips. Terminal buds fail to grow and eventually die. Leavesare distorted with margins curled downwards or upwards, Fruits crack, roots are abnormallyshort, thick and crooked. Excess Ca produces alkalinity and reduces the availability of nutrientssuch as P, K, Mn, Fe and Zn.

Magnesium

It is a constituent of chlorophyll, protoplasm, chromosomes,etc. It is a catalyst in several enzymes and is essential for formationof carbohydrates, oils, fats and vitamins. Deficiency symptoms firstappear in older leaves. The most prominent symptom is yellowingof leaf margins that progresses through the interveinal tissuetowards the rib. The veins and adjacent tissues remain green.Excessive Mg levels may result in either K or Ca deficiency in plants.

Sulphur

Sulphur is present abundantly in leaves. It is a constituent ofcystine, methionine, proteins and fatty acids. It increases root growth,nodule formation and stimulates seed formation. Chlorosis is firstobserved on the young leaves in sulphur deficient plants. Shootgrowth is restricted. Leaf area and fruiting is reduced. Leaves fallearly. Excess of Sulphur results in reduced leaf size, leaf burning ormottling with a yellow or bronzed colouration, accompanied by leafabscission.

Iron

Iron acts as a catalyst in formation of chlorophyll and inseveral enzymes. It is a key element in various reactions ofrespiration, photosynthesis and reduction of nitrates andsulphates. In its deficient plant interveinal chlorosis is first seen inyoung terminal leaves. In severe cases, the new leaves unfoldcompletely, devoid of green colour but veins usually turn greenlater. The fine network of veins is distinctively green against a

Iron deficiency symptoms-yellowing of youngest leaves

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yellow back ground. Plants seldom show Fe toxicity symptoms as solubility of Fe in the soilsolution is rather low.

Zinc

It is required for synthesis of tryptophan, a precursor of auxin,Indole acetic acid. It is essential for carbon dioxide evolution andutilization, carbohydrate and phosphorus metabolism, and synthesisof proteins. Its deficiency leads to short internodes, small narrowleaves, interveinal chlorosis and shoot and branch dieback. In advancedstage, small, narrow, terminal leaves are arranged in whorls givingrise to a typical 'rosette' or little leaf symptoms. Root growth isrestricted. The symptoms disappear as the season advances. Soilsderived from parent material rich in zinc or impregnated with seepage water from Zn ore,excessive fertilization with Zn in acid soils causes toxicity in plants. Toxicity of Zn can be reducedby liming or by adding superphosphate to the soil, thus reducing the solubility and absorptionof Zn.

Manganese

Manganese accumulates in leaves more than seeds and stalk tissue. Itplays an essential role in respiration, nitrogen metabolism, chlorophyllsynthesis and breakdown. Deficiency symptoms appear soon after the leafis fully expanded and persists throughout its life. It is characterised by apattern of leaf chlorosissome what between that caused by magnesium andiron deficiency. High acidity leading to greater solubility of Mn; additionof acid forming fertilizers and regular application of MnS04 over many yearsor poor soil aeration cause Mn excess in soils.

Copper

It is required in oxidation-reduction reactions, photosynthesis, respiration, carbohydrate/nitrogen balance, chlorophyll and vitamin A formation, biosynthesis and activity of ethylene infruit ripening. Dieback, gum pockets at nodes of twigs and brownish excrescence on fruits, twigsand leaves are common in copper deficient plants. Chlorotic and small leaves sometimes alsoshow brown or bronze areas. Fruits have thick peel, lack juice and are insipid with a tendency ofcracking or splitting of rind. Excess of copper results in reduced plant and root growth with lessbranching, more thickening and abnormally dark root-lets.

Zinc deficient mango shootshave shortened internodes,resulting in leaf rosetting.

Manganese deficientorange; leaves develop

a mottled pattern oflight and dark green.

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Boron

It plays a part in flowering, fruiting, photosynthesis, hormonemovement and action, cell division, differentiation anddevelopment, sugar translocation, pollen germination, pollen tubegrowth, rooting and active salt absorption. In its deficiency, terminalbuds fail to open or abort and twigs die-back. Leaves are darkergreen, boat like, brittle and abscise early, starting from the shoottips. Fruits are malformed, hard, misshapen with rough skin. Corkyareas develop in cortex and browning in core region. In somecultivars, fruits crack. Available B content of 0.5 ppm in soil maycause a deficiency in some plants but leaves (>5 ppm) become toxic for normal plant growth.

Molybdenum

The Mo plays an important role in nitrogen metabolism. It isconstituent of two major plant enzymes namely, nitrogenous and nitratereductase. It helps in fixation of atmospheric nitrogen in legume crops.Deficiency symptoms develop on leaves as yellow spots. In late summer,large yellow spots are apparent with gum and corky cells forming onthe lower leaf. Fruit yield is adversely affected. Mo toxicity is not reportedin plants

Chlorine

It is involved in the oxygen evolution in primary reactions of photosynthesis, cellmultiplication and turgor production in guard cells. Chlorosis, necrosis, unusual bronzediscolouration of foliage and wilting of plants is seen in Cl deficient plants. High levels of Clresult in depressed growth, chlorosis, burning of tips and margins of leaves, bronzing, prematureyellowing and abscission of leaves.

Nickel

It is an essential part of enzyme in nitrogen metabolism. Leaf tips with dead spots.

These deficiency symptoms can be overcome by supplying nutrients artificially. Nutrientscan be supplied to vegetables by organic manures and chemical fertilizersin appropriatequantities. Organic manures not only add the essential nutrients to the soil but they also improvethe soil texture and structure. Nitrogen is applied in the form of farmyard manure andinorganic fertilizers such as urea, ammonium sulphate, calcium ammonium nitrate (CAN)etc. Phosphorus is applied in the form of phosphate such as single super phosphate, rock

Boron deficient papaya fruitsdevelop bumps.

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phosphate, di-ammonium phosphate etc. Potash is applied in the form of sulphate or chlorideof potassium etc. For controlling of micronutrient deficiency, several water soluble fertilizersspecific to micronutrients are available like borax (for boron).

Activity

Visit nearby fruit and vegetable farms and collect samples of plants showing someabnormalities. Try to diagnose the symptoms associated with nutrient deficiency and prepareherbarium.

CHECK YOUR PROGRESS

1. Write the criteria of essentiality of an element. Classify all essential nutrients on thebasis of their requirement.

2. Write five nitrogenous andphosphatic fertilizers along with their percent N and P2O5contents.

3. Classify all essential nutrients on the basis of their mobility in plant system.

4. Write the functions and deficiency symptoms of nitrogen, calcium, zinc and boron inplants.

5. Define the following terms

a) Mobile nutrients b) essential nutrient c) Macro nutrient

d) Secondary nutrient e) Fertilization f) Mineral nutrition

FILL IN THE BLANKS

1. Deficiency symptoms of nitrogen first appear on……………leaves.

2. Ca, Mg, and Sare known as ______________________ nutrients.

3. A nutrient which plays a unique role in osmotic regulation, opening and closing ofstomata is …………………

4. Elements that provide basic structure to the plant are……………,…………….and……………….

5. Nutrient required for synthesis of tryptophan, a precursor of auxin, Indole acetic acidis……………………

6. Deficiency of……………. causes 'little leaf" in citrus.

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Chadha, K.L. 2001. Handbook of Horticulture. Indian Council of Agricultural Research,NewDelhi.

Chattopadhyay, T.K. (2012). A Textbook on Pomology, Vol. 1 (Fundamentals), Kalyani publishers,Ludhiana, India.,

Singh, J. (2012). Basic Horticulture. Kalyani publishers, Ludhiana, India.

http://www.agritech.tnau.ac.in

http://www.puricare.co.za

http://www.miami-dade.ifas.ufl.edu

66

Organic and Inorganic Manures and TheirMethods of Application in

Horticultural CropsOBJECTIVES

After studying this chapter, students will be able to:• Gain basic knowledge about organic and inorganic manures and fertilizers.• Understand the importance and principles of fertilizer application to horticultural

crops• Learn about different methods of fertilizer application.• Decide on the most appropriate manures and fertilizers and their suitable method of

application for a given situation.

INTRODUCTION

For optimum growth and production of horticultural crops,application of fertilizers is mostimportant. Horticultural crops require nutrients for its growth and development which areabsorbed through soil. In order to get maximum benefit from manures and fertilizers, theyshould not only be applied in proper time and in right manner but there are many other aspects,which should also be given due consideration. Different soils react differently on fertilizerapplication. Similarly, the N, P, K requirements of different crops are different and even for asingle a crop, the nutrient requirements are not the same at different stages of growth.Now,certain questions may arise in your mind. What are the different methods of fertilizer application?Is there a choice to practice a particular method fertilizer application? Can any chemical fertilizerbe sprayed on crops?

As we learnt about essential plant nutrients, their deficiency symptoms and various typesof manures and fertilizers in chapter 5, let's revise it. There are 17 elements which are essentialfor plants namely, carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus(P),potassium(K), calcium(Ca), magnesium(Mg),sulphur(S), Iron(Fe), manganese(Mn), zinc(Zn),copper(Cu), molybdenum(Mo), chlorine (Cl), boron (B) and Nickel (Ni) . Manures and fertilizersare major nutrient supplying sources to plants. In this chapter we will learn about various methodsof fertilizer application employed for optimum growth and yield of horticultural crops. Adeficiency of any of these nutrient elements can limit plant growth and development and,ultimately, yield. Most soils contain sufficient amounts of the micronutrients needed to support

CHAPTER 6CHAPTER 6

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plant growth. However, soils may be lacking in some of the macronutrients, particularly nitrogen,phosphorus and potassium. Therefore, it becomes necessary to ensure the presence of all theessential elements supplied by the soil in the right quantities and the right chemical forms forplant use. This is done by supplying organic matter and by the judicious use of fertilizers andmanures in order to supplement the nutrients required by the plants from soil to increase cropyield vis-a-vis to maintain/ improve the soil fertility. Continuous cropping and several otherfactors necessitate the use of manures and fertilizers. The dose, method and time of applicationdepend on crop, soil, fertilizer/manure and climatic factors of the region.

Inorganic and organic manures

Inorganic manures: These are industrially manufactured chemicals containing highernutrient content than organic manures, while fertilizer grade refers to the guaranteed minimumpercentage of N, P2O5 and K2O contained in the fertilizer material. Composition of differentfertilizers commonly used in horticultural crop production is given in Table 1. Nutrient input islost either through leaching, runoff, volatization, fixation by soil or consumption by weeds, etc.Coated fertilizers namely, urea supergranules, tar-coated urea and sulphur-coated urea makenutrients available slowly and prevent wastage. Use of nitrification inhibitors can also be anapproach for increasing the nitrogen-use efficiency.

In India, fertilizers consumed are of 5 types:

1. Nitrogenous fertilizers

2. Phosphatic fertilizers

3. Potassic fertilizers

4. Complex fertilizers

5. Fertilizer mixtures

1. Nitrogenous fertilizers

These fertilizers supply nitrogen. The common nitrogenous fertilizers are ammoniumsulphate, calcium ammonium nitrate and urea etc. Ammonium sulphate and urea are by far themost important nitrogenous fertilizers used by Indian farmers.

2. Phosphatic fertilizers

These fertilizers are chemical substances that contain nutrient phosphorus in absorbableform. The primary material of phosphatic fertilizers is rock phosphate. The commonly usedphosphatic fertilizers are Single super phosphate(16% P205, 20% calcium and 12% sulphur),Dicalcium phosphate(32-36% P205) triple super phosphate (46-48% P205).

Any natural or manufactured material, dryor liquid added to soil in order to supplyone or more plant nutrients other thanlime or gypsum is known as fertilizer.

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Bone meals have been used as manures for time immemorial. Bone meals are of two kinds(i) Raw bone meal and (ii) Steamed bone meal. Raw bone meal contains about 25% P205 and 4%N which is in the slow acting organic form. Steam bone meal contains 25-30% totalphosphorus(P205) and about 1-2% N. It contains about 25% citrate soluble phosphorus (P205).Steam bone meal is applied to soil few days before sowing of crop.

Basic slag: It is a by product of the steel industry where the original iron ores containappreciable amounts of phosphorus. It is a grayish black powder with a very high specific gravity.It contains 8-12% P205.

3. Potassic fertilizers

These fertilizers are applied to soil to supply the plant with potassium (K) one of theessential elements for plant growth. Main potassic fertilizers used today are Muriate of Potash(60%K2O), Sulphate of Potash(48 to 52% K2O).

4. Complex fertilizers

Straight fertilizers versus Complex fertilizers:

Straight fertilizers supply only one of the primary fertilizer elements, either N or P or K forplant growth, e.g., urea. Complex fertilizers supply more than one fertilizer elements needed forcrop growth. When they supply any of the two of the fertilizer elements needed for plant growth,they are called incomplete fertilizer, e.g. Mono-ammonium phosphate (11.0% N and 48.0% P205)and Diammonium phosphate (21% N and 52% P205). When they supply all the three fertilizerelements for crop growth, they are called complete complex fertilizer, e.g., Nitrophosphate (15%N, 15% P205 and 15% K2O).

5. Mixed fertilizers:

A mixed fertilizer means a mixture of more straight fertilizers, e.g., ammonium sulphateand single super phosphate may be thoroughly mixed to get a mixed fertilizer.

Advantages of mixed fertilizer

• Two or more fertilizer elements are added together to make a mixed fertilizer to beapplied m the field. Less labour is, therefore, required for application of a mixedfertilizer.

• Fertilizer elements can be more uniformly applied to the field especially when theyare required in small quantities.

• Mixed fertilizer can easily be drilled because of good physical condition.

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Disadvantages of mixed fertilizer:

• The use of mixed fertilizer does not permit the use of single nutrient which may berequired by the crop at a certain stage.

• The illiterate farmers cannot effectively control the quantity of plant food nutrientspresent in the mixture.

Types of mixed fertilizers:

Mixed fertilizers are of two types(i) Open formula mixture and (ii) Close formula mixture

In open formula mixed fertilizer, manufacturer discloses the name and quantities of thestraight fertilizers that are constituents of the mixed fertilizer whereas in close formula mixedfertilizer, firm does not disclose the constituents of the fertilizer.

Sulphur containing fertilizers

These are the chemical substances containing the nutrient 'S' in the nutrient form ofabsorbable sulphate anions S04-2 .The important 'S' containing water soluble fertilizers areAmmonium sulphate (24% S), Potassium sulphate (18% S), Ammonium sulphate Nitrate (15%S)and Super phosphate (12%S).

Micronutrient fertilizers:

Iron fertilizers: These are generally water soluble substances predominantly sprayed asfoliar nutrients on the crops. Plants absorb iron in the form of Fe-2. Commonly used iron fertilizersare Ferrous sulphate (FeS04. 7H20) contains 20% Fe (water soluble).

Manganese fertilizers: Manganese sulphate (MnS04. 4H20.) is pink salt containing 24% Mn,suitable for foliar application.

Zinc fertilizers: Zinc sulphate (ZnS04 7H20) is water soluble salt whitish in colour containing23% Zn. It can be applied as foliar or in soil.

Boron fertilizers: Borax (Na2B04. 10H2O) is water soluble white salt which can be appliedas soil dressing/foliar spray. It contains 11% boron.

Other micronutrients like copper and molybdenum are supplied through copper sulphateand sodium molybdate, respectively.

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Table 1. Composition of common inorganic manures.

Fertilizer Composition (%)

N P2O5 K2O Miscellaneous

Anhydrous ammonia 82

Ammonium sulphate 20.6

Calcium ammonium nitrate 25

Urea 46

Single superphosphate - 16 12 S

Diammonium phosphate 16 and 18 48 and 46

Rock-phosphate 20-40

Muriate of Potash 60

Ferrous sulphate 19 Fe

Borax 11 B

Boric acid 17 B

Manganese sulphate 26 Mn

Basic zinc sulphate 55 Zn

Copper sulphate 21 Cu

Organic manures: These are plant and animal wastes that are used as nutrients afterdecomposition. Plants are directly or indirectly the source of recyclable materials. They providevarious types of crop residues. When crushed, seeds of oil crops leave behind oil cakes. Biomassof several uncultivated plants is also recyclable. Human and animal wastes are largely the residuesof plant products ingested either by humans or by domesticated animals. Organic manures andleguminous green manures are most valuable from crop nutrition point of view, whereasfarmyard manure, crop residues and composts are most important from utilization and organicrecycling point of view. Organic resources reduce the mining of soil nutrients and improve soilproductivity, by improving soil tilth, aeration, water-holding capacity and activity ofmicroorganisms. Organic manures are classified into bulky organic manures and concentratedorganic manures depending on the nutrient content in them. Nutrient content of commonly usedorganic manures have been given in Table 2.

Bulky organic manures

Farmyard manure: The decomposed mixture of dung and urine of farm animals alongwith litter and left over materials from roughages or fodder fed to cattle is farmyard manure.

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Quality of farmyard manure can be improved by concentrated feeds given to the cattle. Cottonseed, cotton seed cake, linseed meal, wheat bran, grain husk, ground nut cake etc. are rich in N,P, Mg, and S.

Compost: Composting is a process in which both aerobic and anaerobic micro-organismsdecompose organic matter under medium to high temperature and low carbon-nitrogen ratio ofrefuse. Farm compost is mass of rotted organic matter made from farm waste like sugarcanetrash, paddy straw, weeds and other plants, while town compost is mass of rotted organic mattermade from town refuses like night soil, street sweepings and dustbin refuse.

Sewage and sludge: In modern system of sanitation adopted in cities, water is used forremoval of human excreta and other wastes, called as sewage. Solid portion is sludge while theliquid portion is sewage water. Both sludge and sewage water are separated and givenpreliminary fermentation and oxidation treatments to reduce bacterial contamination andoffensive smell and also to narrow down the C: N ratio.

Vermi-compost: It is the compost prepared with the help of earthworms. Earthwormsconsume large quantities of organic matter, excrete soil as casts which have several plant growthpromoters, enzymes rich in plant nutrients, beneficial bacteria and mycorrhizae. Vermicompostis a rich mixture of major and minor plant nutrients. It increases total microbial population ofnitrogen fixing bacteria, actinomycetes and symbiotic association of mycorrhiza on plantroot system. Earthworm casts harbour a large number of vesicular arbuscularmycorrhizal(VAM) propagules which survive for about 11 months. Increased microbial activity improvessoil phosphorus and nitrogen availability. It also improves by using residues as surfacemulches.

Concentrated organic manures

Oil cakes: Oil cakes can be grouped into edible oil cakes which are suitable for cattle feedingand non-edible oil cakes which are unfit for cattle consumption.

Blood meal: An adult cattle gives about 13.6kg blood meal and goat or sheep about 1.36kg.It is effective for all horticultural crops and all types of soils.

Meat meal: The meat is converted into meat meal. It is quick acting and suitable for alltypes of horticultural crops and soils.

Fish meal: Non-edible fish carcasses and fish offal are used to prepare fish meal. These arecrushed and powdered before use.

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Table 2. Nutrient content of organic manures

Organic manures N (%) P2O5 (%) K2O (%)

Poultry manure 3.03 0.63 1.40

Farmyard manure 0.75 0.20 0.50

Vermi-compost 3.00 1.00 1.50

Neem cake 5.22 1.08 1.48

Bio-fertilizers

These are inputs containing micro-organisms capable of mobilizing nutritive elements fromnon-usable form to usable form through biological processes. They are less expensive, eco-friendlyand sustainable and do not require non-renewable source of energy during their production.They improve plant growth and fruit quality by producing plant hormones. They increase thesustainability of soil and make it more productive. They are also useful as bio-control agentssince they control many plant pathogens and harmful microorganisms. Some of the beneficialmicroorganisms are capable of fixing atmospheric nitrogen, while some can increase theavailability of N and P. Different bio-fertilizers available for use for horticultural crops are givenin Table 3.

Table 3. Biofertilizers commonly used for horticultural crops

Biofertilizer Organisms Fixed nutrient

Saprophytes Aspergillus,Trichoderma Decomposes organic matterat a faster rate

Legume inoculants Rhizobium species Fixes atmospheric N inassociation with leguminouscrops

In association with plants Azospirillum High N fixation capacity

Free-living organism Azotobacter Fixes N in neutral to alkalinesoils

Phosphorus solubilizers Pseudomonas striata, PBacilluspolymixa,AspergillusawamoriandPencilliumdigitatum

Endotrophic mycorrhizae Glomus, Gigaspore, Higher N, P, K, Ca and Mg(VAM)

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Integrated nutrient management

It is the use of chemical fertilizers, organic manures, slow-releasing fertilizers, nitrificationinhibitors, vesicular-arbuscular mycorrhizae and nutrient efficient rootstocks either singly or incombination, all at a time in a definite sequence during the growth developmental stages ofplant for economic and efficient use of nutrients without having any adverse effects on soilhealth and environment.

Principles of fertilizer application

The basic principle of fertilizer application is to make the nutrients readily available to theplants as per their requirement without much wastage and harmful effects on soil. Usually largerquantities of fertilizers are added to clayey soils at longer intervals than to sandy soils becauseclayey soils are richer in humus than sandy soils and both clay and humus have a high capacityto retain nutrient ions by a phenomenon called Base Exchange. These adsorbed nutrient ions arenot lost by leaching, can be gradually taken up by the plant roots. If a heavy dose of watersoluble fertilizer is applied to sandy soils, most of it will be leached down by high rainfall in thehumid regions.

Difference between manures and fertilizers

Sl. No. Characteristics Manures Fertilizers

1. Origin Plant, animal, human residue Chemically manufactured

2. Type Natural product Artificial product

3. Nutrient content Low / less concentrated High / more concentrated

4. Availability of Slow releasing May or may not be readilynutrient available

5. Effect on soil Improves physical property Do not improves physicalhealth of soil property of soil

Quantities of fertilizers to be applied

Different crops require different quantities of nutrients. Fertilizer dose is calculated on thebasis of requirement of plants for its various physiological activities. While applying fertilizers,nutritional status of soil is taken into account. After deducting contribution of soil, rest amountis replenished externally by the application of fertilizers.

Time of application of fertilizers

Generally, the manures are applied in the field before the onset of monsoon. With theappearance of rain, the manures are decomposed well and their nutrients become readily available

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to plants. The fertilizers are applied at the time of active growth of plants so that the nutrientsmay be absorbed by the roots. Generally, the plants remain active during February- March andJuly and new growth emerges on the plant. During these times, fertilizers must be applied. Incase of bearing plants, the manures and fertilizers are applied to cope with nutritional requirement.Under such circumstances, the manures and fertilizers must be applied one month before thecommencement of flowering in plants. Phosphatic fertilizers being less soluble should be appliedabout 20 days before the commencement of new growth. Nitrogenous fertilizers being highlysoluble and hence prone to leaching losses should be applied in split doses. Half of therecommended dose of nitrogen should be given before commencement of flowering and resthalf dose is given after fruit set. This holds true especially in case of fruits. In case of vegetables,the recommended doses of fertilizers are applied at the time of sowing, transplanting and alsoduring growing. Nitrogenous fertilizers are given in splits to support production.

Methods of application

For maximized efficiency, fertilizer should be applied in root zones of the plants. Themethods by which fertilizers can be applied are discussed as under:

1. Broadcasting: It refers to spreading fertilizers uniformly all over the field. Suitable for cropswith dense stand, the plant roots permeate the whole volume of the soil, large doses of fertilizersare applied and insoluble phosphatic fertilizers such as rock phosphate are used. Broadcastingof fertilizers is of two types.

(i) Broadcasting at sowing or planting (Basal application): The main objectives ofbroadcasting the fertilizers at sowing time are to uniformly distribute the fertilizerover the entire field and to mix it with soil.

Advantages: Fast and economical.

Disadvantages: High nutrient losses, low uniformity. P efficiency is only 1/3 to 1/4 that ofbanding

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(ii) Top dressing: It is the broadcasting of fertilizersparticularly nitrogenous fertilizers in closely sowncrops like paddy and wheat, with the objective ofsupplying nitrogen in readily available form togrowing plants.

Disadvantages of broadcasting

The main disadvantages of application of fertilizers through broadcasting are:

i) Nutrients cannot be fully utilized by plant roots as they move laterally over longdistances.

ii) The weed growth is stimulated all over the field.

iii) Nutrients are fixed in the soil as they come in contact with a large mass of soil.

2. Placement: It refers to the placement of fertilizers in soil at a specific place with or withoutreference to the position of the seed. Placement of fertilizers is normally recommended when thequantity of fertilizers to apply is small, development of the root system is poor, soil has a lowlevel of fertility and to apply phosphatic and potassic fertilizers. The most common methods ofplacement are as follows:

(i) Plough sole placement: In this method, fertilizer is placed at the bottom of the ploughfurrow in a continuous band during the process of ploughing. Every band is coveredas the next furrow is turned. This method is suitable for areas where soil becomesquite dry upto few cm below the soil surface and soils having a heavy clay pan justbelow the plough sole layer.

(ii) Deep placement: It is the placement of ammonical nitrogenous fertilizers in thereduction zone of soil particularly in paddy fields, where ammoniacal nitrogen remainsavailable to the crop. This method ensures better distribution of fertilizer in the rootzone soil and prevents loss of nutrients by run-off.

(iii) Localized placement: It refers to the application of fertilizers into the soil close to theseed or plant in order to supply the nutrients in adequate amounts to the roots ofgrowing plants. The common methods to place fertilizers close to the seed or plantare as follows:

(a) Drilling: In this method, the fertilizer is applied at the time of sowing by meansof a seed-cum-fertilizer drill. This places fertilizer and the seed in the same rowbut at different depths. Although this method has been found suitable for theapplication of phosphatic and potassic fertilizers in cereal crops, but sometimes

76

germination of seeds and young plants may get damaged due to higherconcentration of soluble salts.

(b) Side dressing: It refers to the spread of fertilizer in between the rows and aroundthe plants. The common methods of side-dressing are:

(i) Placement of nitrogenous fertilizers by hand in between the rows of cropslike maize, sugarcane, cotton etc., to apply additional doses of nitrogen tothe growing crops and

(ii) Placement of fertilizers around the trees like mango, apple, grapes, papayaetc.

3. Band placement: If refers to the placement of fertilizer in bands. Band placement is of twotypes.

(i) Hill placement: It is practiced for the application of fertilizers in orchards. In thismethod, fertilizers are placed close to the plant in bands on one or both sides of theplant. The length and depth of the band varies with the nature of the crop.

(ii) Row placement: When the crops like sugarcane, potato,maize, cereals etc., are sown close together in rows, thefertilizer is applied in continuous bands on one or both sidesof the row, which is known as row placement.

4. Pellet application: It refers to the placement of nitrogenous fertilizer in the form of pellets2.5 to 5 cm deep between the rows of thepaddy crop. The fertilizer is mixed with thesoil in the ratio of 1:10 and made smallpellets of convenient size to deposit in themud of paddy fields.

Advantages of placement of fertilizers

The main advantages are as follows:

(i) When the fertilizer is placed, there is minimum contact between the soil and thefertilizer, and thus fixation of nutrients is greatly reduced.

(ii) The weeds all over the field can not make use of the fertilizers.

(iii) Residual response of fertilizers is usually higher.

Row placement

Seed cum fertilizer drill is an implement usedto sow the seed in rows as well as to apply thefertilizers at the same time

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(iv) Utilization of fertilizers by the plants is higher.

(v) Loss of nitrogen by leaching is reduced.

(vi) Being immobile, phosphates are better utilized when placed.

The common methods of applying liquid fertilizers are as follows:

1. Starter solutions

It refers to the application of solution of N, P2O5 and K2O in the ratio of 1:2:1 and 1:1:2 toyoung plants at the time of transplanting, particularly for vegetables. Starter solution helps inrapid establishment and quick growth ofseedlings. The disadvantages of startersolutions are:

(i) Extra labour is required, and

(ii) the fixation of phosphate ishigher.

2. Foliar application:

It refers to the spraying of fertilizer solutions containing one or more nutrients on the foliageof growing plants. Several nutrient elements are readily absorbed by leaves when they aredissolved in water and sprayed on them. The concentration of the spray solution has to becontrolled; otherwise serious damage may result due to scorching of the leaves. Foliar applicationis effective for the application of minor nutrients like iron, copper, boron, zinc and manganese.Sometimes insecticides are also applied along with fertilizers.

3. Application through irrigation water (Fertigation): Itrefers to the application of water soluble fertilizers throughirrigation water. The nutrients are thus carried into the soil insolution.

Can any chemical fertilizer be sprayed on crops?• Only those fertilizers that do not scorch

(burn) leaves are sprayed.• Usually micronutrients, which are required

in low rates, are foliar sprayed.• Urea sprays are used for supplying

nitrogen

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4. Injection into soil: Liquid fertilizers for injection into the soil may be of either pressure ornon-pressure types.Non-pressure solutions may be applied either on the surface or in furrowswithout appreciable loss of plant nutrients under most conditions.Anhydrous ammonia mustbe placed in narrow furrows at a depth of 12-15 cm and covered immediately to prevent loss ofammonia.

5. Aerial application: In areas where ground application is not practicable, the fertilizersolutions are applied by aircraft particularly in hilly areas, in forest lands, in grass lands or insugarcane fields etc.

Precautions in fertilizer use

• It is better to get the soil tested from soil-testing laboratory. The amount of fertilizer(s)should be calculated based on soil test for balanced use of nutrients.

• Secondary nutrients like sulphur should be used either alone or through sulphurbearing fertilizers. In acid soils, calcium and magnesium should be maintained at theoptimum level.

• Micronutrient should be applied whenever necessary. In acidic soils boron andmolybdenum, and in alkaline soils, iron, zinc and manganese should be madeavailable. Phosphate rich calcareous soils may show zinc deficiency problems.

• Fertilizers should be selected on the basis of soil characteristic. Avoid acid fertilizersin acid soils and basic fertilizers in alkaline soils.

• Improve soil structure through the addition of organic manure and gypsum. Blackand alluvial soils should be deep ploughed.

• Use of high yielding varieties, irrigation at an appropriate time and amounts, removalof weeds, spacing and plant population etc. should be given due consideration.

ACTIVITY/EXERCISE

1. Know the manures and fertilizers available and being used in your area by visitingco-operative society and prepare a list of the same mentioning contents of particularnutrient present in them.

2. Apply the available manure and fertilizers in your kitchen garden/farm/orchard byemploying a particular suitable method of fertilizer application and recordobservations in respect of growth and fruiting of the crops being grown.

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CHECK YOUR PROGRESS

1) What do you mean by organic and inorganic manures? List five inorganic manuresalong with their nutrient content.

2) Write the various types of concentrated organic manures.

3) What is vermi-compost? How does it differ from farm yard manure?

4) What is the principle of fertilizer application? Enlist the different methods of fertilizerapplication.

5) When is broadcasting of fertilizers practiced?What are the drawbacks with broadcastapplication?

6) What are the different methods of placing the fertilizers? When is placement offertilizers practiced?

7) What are the advantages of band placement?

8) What is foliar application of fertilizers?

FILL IN THE BLANKS

1. Usually larger quantities of fertilizers are added to…………….soils at longer intervalsthan to sandy soils.

2. Use of ……………….inhibitors can also be an approach for increasing the nitrogen-use efficiency

3. Vermi-compost is prepared with the help of…………………………

4. The application of water soluble fertilizers through irrigation water is knownas…………………….

5. The fertilizers are applied at the time of……………growth of plants

6. The manures and fertilizers must be applied one month before the commencement of…………………….. in plants.

7. Nitrogen content present in Calcium ammonium nitrate is……………percent.

8. The application of water soluble fertilizers through irrigation water is referred to as……………………………….

9. Foliar application is effective for the application of ……………nutrients.

10. The application of fertilizers in orchards is done through……………..method.

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Chadha, K.L. 2001. Handbook of Horticulture. Indian Council of Agricultural Research,NewDelhi.

Chattopadhyay, T.K. (2012). A Textbook on Pomology, Vol. 1 (Fundamentals), Kalyani publishers,Ludhiana, India.,

Singh, J. (2012). Basic Horticulture. Kalyani publishers, Ludhiana, India.

http://www.agritech.tnau.ac.in

81

Water Management inHorticultural Crops

OBJECTIVES


• Learn about water management and various methods of irrigation including microirrigation techniques

• Select the suitable irrigation system for different horticultural crops.

• Manage the horticultural crops by making efficient uses of available water resources.

• Decide on the most appropriate irrigation system for a given situation.

INTRODUCTION

Horticultural crops require significant amounts of water due to their perishable nature. Infruit trees, water stress not only affects the current season's crop, but future crops as well due totheir perennial nature. Since water is such a critical component of the growth and developmentof horticultural crops, it is recommended that none of these crops be established without assuredirrigation facilities. Water requirement of a plant depends on its growth habit and life period.Plants differ greatly in their water requirements. Now, certain questions may arise in your mind.Is there a choice to practice particular method of irrigation? What is the most economic methodof irrigation? This chapter will cover the basic information regarding various irrigation systemsused in horticultural crops.

Water Requirement:

Water requirement of a crop is the quantity of water needed for normal growth, developmentand yield and may be supplied by precipitation or by irrigation or by both. Water is neededmainly to meet the demands of evaporation (E), transpiration (T) and metabolic needs of theplants. The water requirement of any crop is dependent upon the following factors:

• Crop factors like variety, growth stage, duration, plant population and growing season.

• Soil factors like texture, structure, depth and topography.

• Climatic factors like temperature, relative humidity and wind velocity.

• Crop management practices like tillage, fertilization, weeding etc.

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Irrigation Systems:

Irrigation may be defined as artificial supply of water to support plant growth andproduction in the absence of adequate supply of water through rainfall. Water is the mainconstituent of plants. It performs the following important functions in plants:

• Water is essential for the germination of seeds and growth of plants.

• During the process of photosynthesis, plants synthesize carbohydrates from carbondioxide and water. Therefore, water is one of the essential components for the plant.

• Water acts as a solvent for fertilizers and other minerals, which are taken up by theplant roots in the form of solution. Thus, water serves as the medium in which plantsabsorb soluble nutrients from the soil.

• Water serves as medium for transport of chemicals to and from cells.

• Water pressure in plant cells provides the firmness to the plants.

Irrigation is very important in horticultural crops as sufficient moisture must be maintainedin the soil for obtaining the optimum yield of quality fruits. The aim of irrigating the cropsshould be to wet the entire root zone without allowing any wastage of water beyond the rootzone. The irrigation system has to be properly devised so that the water requirements of thecrops are met at the minimum expenditure without any wastage of water. Various types ofirrigation techniques differ in how the water obtained from the source is distributed within thefield. In general, the goal is to supply the entire field uniformly with water, so that each plant hasthe amount of water it needs, neither too much nor too little.

Many factors determine the suitability of irrigation system for a particular crop. Severalmethods are employed for the irrigation of horticultural crops depending on the type of cropsgrown whether fruit plants or vegetables or flowers or plantation crops, age of the tree, the soiltopography and the availability of irrigation water. Thus the system of irrigation must be decidedin relation to the varying field conditions. Choose the correct system for a particular crop andsituation.

Irrigation is generally applied to horticultural crops by flooding on the field surface (Surfaceirrigation), applying beneath the soil surface (sub surface irrigation), spraying under pressure(sprinkler irrigation) or by applying in drops in the crop root zone (Drip irrigation). Severalwater application methods are practiced to suit different soil types, the topography of the land,crops to be irrigated and costs. Different systems of irrigation commonly adopted in horticulturalcrops are as follows:

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A. Surface irrigation: In this method, water is applied to the crop by flooding it on the soilsurface. In this system whole of the area is irrigated through one head i.e. without sub-divisionof the unit area into small plots. Irrigation water used in this case is excessive as the entire fieldis to be wetted to meet the need of the excessive root system. It provides fully saturation of rootzone. In this system, the wastage of water is more and this also leads to excessive weed growth.This method is simple in layout and operation. More than 90 % of irrigated area in India is undersurface irrigation. This method may be classified as border, furrow and basin.

1. Border method: In this method, border are formed by making number of stripswhich are separated by ridges. An irrigation channel runs along the upper end of theborders.

2. Furrow system: This system is suitable in areas where the orchards are planted insloppy land. In this system the water moves slowly in furrows in the area betweentree rows. The trees are fed through the lateral movement of water. The consumptionof water is less in this system and there is no risk of bark diseases. Saturation of rootzone is comparatively less. Intercropping or green manuring is not possible in furrowsystem. This system is suitable for old orchard.

3. Basin system: In this method, a small circular basin is provided around the tree trunk.These basins are linked directly with one another through straight channel. There isless wastage of water and it checks weed growth. Water passing through the channeltouches the tree trunk directly and hence risk of bark diseases is involved. The waterflow also draws away the manure from the tree basins and deposits it at the end of thechannel. This system is suitable for young fruit plants below 1- 2 years of age. Thissystem is useful for loamy soils.

4. Modified basin system: This system is an improvement over the basin system. In thissystem, main channel runs in between the tree lines and the basins are linked with itindependently through small sub-channels. The only drawback of this system is thatthis needs more attention to block the sub channels after the basin has receivedadequate water. The size of the basin is increased with the extension of the leaf drip ofeach tree every year. Intercropping is not possible in this system. This is a good systemof irrigation for the young orchard upto 6-8 years of age and also for the arid- irrigatedareas where there is a shortage of water.

In improved modified basin system, the basins are linked with the channel passingthrough along the side of these basins. This system avoids the risk of bark diseases andintercropping is possible.

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B. Sub-surface irrigation: In this system, perforated or porous pipes are laid out undergroundbelow the root zone and water is led into the pipes by suitable means. In either case, the idea isto raise the water by capillary movement.

C. Sprinkler system: This system is used wherewater supply is not adequate. The water is pumpedwith pressure through the sprinklers attached topipes and these sprinklers are adjusted in such amanner to overlap upto one fourth area covered bythe other sprinklers. These are then moved to thenext point after sufficient percolation hastakenplace. This system is very costly and is suitable inareas where the sub surface water is not fit and thesoil is uneven or sloppy and the water supply is not regular from the canals. There is considerablesaving in water used through sprinkler irrigation than surface irrigation. The initial, operationaland maintenance costs are high. It is suitable for the full grown orchards and vegetable crops.

D. Drip system: This is system of irrigation which supplies water to the plant equivalent to itsconsumptive use. This is highly water use efficient system of irrigation. The water is suppliedwith pressure after filtering it through the pipes with attached drippers designed to supplywater in drops. These drippers are placed around the plant in a circular pattern and the percolatingwater moves down and side ways wetting the root zone. This system requires regular watersupply. Advantages of drip irrigation system are:

• Wastage of water through percolation, seepage and evaporation is checked as thewater is carried through main lines and laterals. There is 30-70% saving of water.

• Uniform distribution of water

• The labour requirement is minimized considerably.

• Easily adaptable in hilly and undulating lands

• Reduced weed problem.

• Lower quality water of water can be used.

• Increased plant growth and yield.

• Ideal for poor soils and provides better root system to the trees.

• Works at low pressure

• Can irrigate at any time of the day.

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• Causes no erosion

• Application of fertilizer can be done.

• Less incidence of diseases

Disadvantages:

• Clogging of drippers due to oxidants and algae

• High initial investment

Fertigation: It is the application of fertilizer or chemicals through the irrigation system. It isa controlled system to supply soluble plant nutrients at the root zone of the irrigated crops.Fertigation is done through tank, ventury or pump systems. The most practical method ofapplying of fertilizers through the irrigation system is by creating a 10% bypass flow of the mainline flow, through an artificial fertilizer mixing tank.

Advantages of fertigation:

1. An opportunity for placement of fertilizer at the vicinity of root zone of the crop alongwith irrigation water which increases in water and fertilizer use efficiency.

2. Deeper penetration into the soil.

3. Avoids is volatilization from soil surface.

4. Easy coordination with specific crop demand.

5. Decrease in labour and energy cost in fertilizer application by making use ofwaterdistribution system.

6. Improves the availability of nutrients and their uptake by roots.

7. Trace elements can also be applied along with major nutrients.

8. Saving of fertilizers.

Fertigation Tank Fertilizer injector

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Limitations of fertigation:

1. Possibility of clogging emitters if the pH of irrigation water and fertilizer sources isnot managed carefully.

2. May result in possible contamination of the drinking water supply if devices are notusedto prevent back flow of nutrients into the well or other water sources.

3. Some of the chemicals are quite corrosive to metal and also cause skin burning issafety devices are not provided to protect the workers against unplanned dischargeor spilling of chemicals.

Irrigation Scheduling:

When to irrigate and how much to irrigate, form the schedule of irrigation. In order toavoid water stress in plants and to obtain good yields of quality fruits, proper irrigation scheduleshould be followed. Scheduling of irrigation in plants is governed by soil, climatic and plantfactors. Some practical approaches used to determine schedule of irrigation are soil moisturedepletion, cumulative pan evaporation and sensational etc.

Critical Period for Irrigation:

Assured supply of water is required at certain stages of plant growth, which are referred toas critical period for crops. If water is not available at critical stages, yield is greatly reduced. Forherbaceous crops, germination is critical stage. Depending upon the crop, critical stages varysuch as head development for cole crops, pod development for beans, tuberizationfro potato,bulb development for onion and garlic, flower development for flower crops, fruit setting anddevelopment for fruit crops.

ACTIVITY/EXERCISE

1. Visit any orchard/vegetable farm of your locality and find out, which system ofirrigation is practiced, predominantly.

2. Prepare a plan for model unit of drip irrigation system along with fertigation unit forone hectare farm area.

CHECK YOUR PROGRESS

1) Define irrigation? Write the important functions of water in plants.

2) Enlist the various systems of irrigation. Discuss the most useful system suitable forareas with water scarcity.

3) Differentiate between flood and furrow systems of irrigation?

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FILL IN THE BLANKS

1. Water requirement of a plant depends on its……………..and ……………..

2. Water serves as the medium in which plants absorb………………..from the soil.

3. In …………..system of irrigation, the wastage of water is more and this also leads toexcessive weed growth.

4. ……………….system of irrigation is suitable for young fruit plants below 1- 2 yearsof age.

5. Application of liquid fertilizer to the root system is possible through……….. systemof irrigation


Bal, J.S. (2007). Fruit growing Kalyani Publishers, Ludhiana, India.



http://www.angrau.ac.in

https://aggie-horticulture.tamu.edu

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Weed Management inHorticultural Crops

OBJECTIVESAfter studying this chapter, students will be able to:• Understand the principles of weed management and classification of weeds.• Describe the different weed control methods.• Select the suitable method of weed management for different horticultural crops.• Plan various cultural practices for weed management in different crops.• Decide on the most appropriate weed management system for a given situation.

INTRODUCTION

Weeds are the most costly category of horticultural pests, causing more yield losses andadded labor costs than either insect pests or crop diseases. In particular, weeds are a constantfact of life in annual row crops, vegetables, and other horticultural crops.

Now certain questions may be arising in your mind. What is weed? How will we identifythe weeds? What will happen if weeds are allowed to grow? How can we control weeds? Youcan face several questions of this category.

Horticultural crops are high value crops and the challenge of weed management is one ofthe important factors to successfully grow them. Weeds compete with crops for light, nutrientsand water, resulting in stressed plants, poor fruit quality and yield. Stressed crops are also moresusceptible to disease and insect problems, while excessive weed growth itself creates higherhumidity in the foliage enhancing disease spread and inviting unwanted insects.

In fruit crops, weed pressure must be addressed throughout the life of the planting. Whencompared to annual crops, perennial culture is a greater challenge, as fall, spring, summer andwinter weeds need to be managed efficiently. Understanding seasonal weed thresholds andintegrating cultural and chemical management becomes even more important in year-roundculture. However, because of different cultural requirements, each crop should be consideredindividually. In this chapter, we will study about weeds, their characteristics and harmful effects,classification of weeds and various methods of weed control.

In India, commercial use of herbicides came in 1980. During the period, the herbicidesregistered a significant growth than insecticides and fungicides. From a mere 2 per cent share of

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the totalpesticide consumption in the seventies in India, herbicides now account for about 11per cent ofthe pesticides market. While this is a very encouraging development, the herbicideconsumptionin our country is still much less than that in developed countries, where herbicidesconstitute 40-50 per cent of the total pesticide consumption.

WHAT IS WEED?

Weeds are unwanted and undesirable plants which interfere with the utilization of landand water resources and thus adversely affect human welfare. They can also be referred as plantsout of place.

Weeds compete with the beneficial and desired vegetation in crop lands, forests, aquaticsystems etc. and pose great problem in non-cropped areas like industrial sites, road/rail lines,air fields, landscape plantings, water tanks and water ways etc.,

Characteristics of weeds

• Weeds are prolific with abundant seed production potentialities e.g. Chenopodiumspp., Amaranthus spp., etc.

• They are persistent and resistant to their control and eradication.

• Weed seeds remain dormant and viable for very long periods e.g. Chenopodium spp.

• Some weeds have very deep root system. They store foods in their rhizomes andreappear every year e.g. Saccharum spp., Cyperus spp.

• Weeds are hardy and can resist any adverse climatic, disease and soil conditions.They result ina severe crop-weed competition.

• Some of the weeds propagate vegetatively e.g. Cynodon dactylon.

• Some weed seeds are similar to crop seeds, therefore their separation becomes difficult.

Harmful effects of weeds

• Weeds compete with crop plants for water, space, light and mineral nutrients.

• Weeds reduce the quantity and quality of farm produce.

• Weeds impair the quantity and quality of animal products e g. thorny weeds withhooks entangle with wool of sheep which graze in pastures.

In the world there are 30,000 weed species, out of these18,000 sps cause damage to the crops. JethroTullfirstcoined the term weed in 1931 in the book “HorseHoeing Husbandry”

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• Weeds harbour insect pests and diseases thus they act as reservoir of infection forcultivated crop plants.

• Weeds increase cost of labour and equipments which ultimately increase the cost ofcultivation of crops.

• Weeds reduce the efficiency of farm equipments.

• Presence of some weeds like Saccharum spp. causes depreciation of land value.

• Some weeds are poisonous and cause health hazards to human beings and animals,for example, Parthanium spp.

Aquatic weeds are very harmful because:

• They impede water flow in canal, channels, rivers, etc.

• They impede drainage

• They are menace to fisheries and other aquatic animals.

• They prevent or spoil the recreational value of the water bodies.

• They pose pollution problem in water.

CLASSIFICATION OF WEEDS

Weeds may be classified in many ways. Some of the classifications are mentioned below:

A. Classification according to life cycle

• Annual weeds (a) Kharif (rainy season) weeds (b) Rabi (winter season) weeds

• Biennial weeds

• Perennial weeds

I. Annual weeds

Kharif annuals: These annuals generally appear with the onset of monsoon and the lifecycle is completed within the rainy season. Few examples are : Echinochloa colonum, Echinochloacrusgalli, Setaria glauca, Digitaria sanguinalis, etc.

Rabi annuals: These annuals start growing up with lowering of temperature in winter andcoincide with the life cycle of the rabi crops. These weeds complete their life cycle before thesummer season starts. Examples are Phalaris minor, Avena fatua, Chenopodium album, Aesphodelustenuifolius, etc.

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In addition to these annuals, there are few plants which complete their life cycle in 2 to 4weeks. Such annuals are known as short lived annuals e.g. Phyllanthus niruri (Hazardana)

II. Biennial weeds

The weeds which complete their life cycle in two years are called biennials. In first yearthey complete their vegetative growth and store food while in the second year their reproductivegrowth or seed formation is completed followed by the death of the plant e.g. Daucus spp.

III Perennials weeds

These are the weeds which complete their life cycle within 3 or more than 3 years. They arecapable of growing/propagating by means of seeds, through under groundstolons, rootsandsuckers e.g. Cynodon dactylon, Saccharum spontaneum, etc.

B. Classification according to plant family

Graminae: Cynodon dactylon, Saccharum spontaneum, Echinochloa crusgalli, Phalaris minor, Avenafatua ,etc.

Solanaceae: Solarium nigrum, Solanum xanthocarpum, etc.

Eupkorbiaceae: Euphorbia hirta, Phyllanthus niruri, etc.

Liliaceae: Aesphodelus tenuifolius

Chenopodiaceae: Chenopodium album

Convolvulaceae: Convolvulus arvensis, Ipomoea spp.

C. Classification according to cotyledon characteristics

With the discovery of 2,4-D as selective translocated herbicide in 1940's, led to a strongrecognition of two great classes, namely, the monocot and the dicot weeds. In general, monocotweeds were found to be resistant to 2,4-Dwhile dicot weeds were susceptible to it. The dicotweeds are often referred to as broad leaf weeds and monocot weeds as narrow leaf or grassy weeds.The exception to this are sedges and cattails which although have narrow leaf yet are not grassyweeds.

Grasses SedgesStem is hollow except at nodes Stem Angular & solidLigulate Does not posses ligulesAlternate or opposite leaves Leaves in whorls around the stem

Eg, Digitaria, Cynadon Cyprus, Scirpus

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D. Classification according to habitat

Depending upon the place of their occurrence, weeds can be classified as:

• Crop land weeds

• Fallow land weeds

• Grassland, pasture or rangeland weeds

• Non-cropped land weeds

• Aquatic weeds

• Forest and woodland weeds

• Lawn and garden weeds

• Orchard and vineyard weeds, and

• Plantation weeds.

This classification is important because for each situation different weeds control measuresare usually employed even though the target weed species may be the same.

E. Classification according to their seriousness as a pest

Common weeds: Those weeds which can be controlled by ordinary good farm weedcontrolpractices. These are mostly annuals and biennials.

Noxious weeds: Those weeds which are difficult to control because of an extensiveperennialroot system or because of other characteristics that make them persistent.

The noxious weeds are again divided into two categories:

Prohibited noxious weeds : Circium arvensis (Canada thistle), Agropyron repens

(Quack grass), Sorghum halepense (Johnson grass).

Restricted noxious weeds : Cuscuta spp. (Dodder), Convolvulus arvensis (Field

Character Monocots DicotdsLeaves Narrow and upright Broad & horizontalVenation Parallel ReticulateRetention of herbicide Less Moreroot system Adventitious Tap rootGrowing point Open OpenCambium (conductive tissue) Scatered IntactExamples Grasses or Narrow Amaranthus spp., Chenopodium album,

leaved weeds Convolvulus arvensis, Phyllanthusniruri,Partheniumhysterophorus, Xanthium strumarium

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bindweed), Allium vineale (Field garlic), Cynodon dactylon (Bermuda grass).

List of common weeds in Horticultural crops:

Echinochloa colonum,Cyperus esculentus, Cyperus rotundus, Digitaria sanguinalis, Eleusineindica,Cynodon dactylon, Amaranthus viridis, Phyllanthus niruri

Ageratum conyzoides, Setaria glauca, Phalaris minor, Avena fatua, Poa annua

Vicia sativa, Medicago denticulate, Ageratum conyzoides, Lantana camara

Imperata cylindrical, Rosa moschata, Berberis, Rubus spp.

CRITICAL PERIOD OF WEED CONTROL

This period has been defined as an interval in the life cycle of the crop when it must be keptweed - free to prevent yield loss. The crop yield level obtained by weeding during this period isalmost similar to that obtained by the full seasons weed free conditions. Horticulture crops arevery sensitive to weed competition, and need to be kept weed-free, from planting, emergence orbud break, until the end of their critical weed -free period. For example, the critical weed freeperiod for bearing apple plants is bud break until 30 days after bloom while in potatoes; it is 4weeks after planting. If the crop is kept weed-free for the critical period, generally no yieldreduction would result. Again, weeds emerging after the critical weed-free period will not affectyield, but control efforts after this time may make harvest more efficient, or reduce weed problemsin subsequent years in perennial crops.

WEED MANAGEMENT

Weed control and weed management are the two terms used in weed science. Weed controlis the process of limiting infestation of the weed plant so that crops can be grown profitably.

Weed management includes prevention, eradication and control by regulated use, restrictinginvasion, suppression of growth, prevention of seed production and complete destruction. Thus

Cyperusrotundus

Sorghum halepense Lantana Convolvulus arvensis

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weed control is one of the aspects of weed management. The various methods of weed controlemployed in horticultural crops are described as under:

A. Preventive methods

Prevention of introduction and spread of the weeds in an entirely new locality is termed aspreventive method. For the matter, it is essential to know that how weed disseminates. Generally,weed spread through the seeds of previous crop, irrigation water, implements and animals etc.If these are taken into account, there will be a check on the spread of the weed. By taking followingmeasures, weed spread can be prevented from entering into a new locality:

1. Sowing of weed-free clean seed. The seeds, contaminated with weed seed, are a goodsource of spread of the weed. It becomes hard to separate the weed-seed from the crop-seed. Forexample, cruciferous crops like radish, cauliflower, cabbage, broccoli etc. are even well mixedwith the seeds of satyanashi(Argemone maxicana). Such impure seeds should be discarded foruse. Seed act is in force which by imposing laws, help regulates the quality of seed.

2. Use of clean implements. While operating agricultural implement like cultivator, harrow,seed drill etc. in weed infested field, care must be taken that multiplication parts of weeds likerhizome, bulb, tubers, stem etc. are not being carried along. The agricultural implements shouldbe cleaned properly.

3. Removal of weed along canal and irrigation channel. Weed seeds get transported throughwater and reach the field. Removal of weed growing along the sides of canal or irrigation channelis necessary.

4. Care in transplanting of seedlings/plantlets. Many horticultural plants like all transplantedvegetables, flowers, and fruits are transplanted in the field with soil attached to their roots.Infestation of soil with weed may contaminate a new field.

5. Use of well rotten manure. Weed seeds have good viability. The seeds of hirankhuri(Convolvulus arvensis) remain viable for as long as 50 years. Doob (Cynodon dactylon) and motha(Cyperus rotundus) seeds viability last for two and five years respectively. For making manure,the cowdung is heaped. If the heaping period is short, the seeds do not lose its viability andgrow in the field wherever manure is applied. Hence, only well-rotten manure should beused.

6. Avoiding passing of cattle from weed infested area. Grazing in weed infested field followedby allowing passage of cattle in new field, favours dissemination of weed seeds. The weed-seedafter passing through alimentary canal of the animal, comes out through dung where it givesrise to weed. Some weed seeds also stick with the legs and skins of the animals and get transportedto some other place where they germinate and grow as weed.

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7. Crop management practices : All such practices which favour the growth of main croponly disfavour the growth of weed. The following management practices have smothering effecton weed and must find place in crop land to prevent weed spread:

Proper crop rotation prevents establishment of weeds.

Higher plant population per unit area smother the growth of weed.

Proper placement of fertilizer in the root zone of the seed favours the growth of crop.The weeds deprive of nutrients and crop growth is restricted.

Fast and vigorous growing varieties by virtue of their larger leaf canopy causesmothering effect on the growth of weed. Such crops should receive preference toprevent spread of the weed.

8. Enforcement of weed laws. In India, many noxious weeds grow in the fields and posegreat economic and health hazards. Noxious weeds are those perennial weeds which arereproduced by seeds, stem, roots and other reproductive parts as well and are very difficult tocontrol. Parthenium hysterophorus, Striga sp., Cyperus rotundus, Cynodon dactylon etc. are noxiousweeds that grow in many horticultural crops. In India, no weed laws are in force except inKarnataka where Parthenium has been declared as a noxious weed. Weed laws help the farmersto avoid the use of mislabelled or contaminated seeds and also help in legally prohibiting weedfrom entering into the country.

9. Quarantine laws. Quarantine laws impose legal restrictions on the movement ofagricultural materials. Had there been adequate quarantine laws, the Parthenium and Argemonewhich widely grow in vegetable and flower fields may not have been introduced in our country.Creating isolation between widely weeds infested area and new area is essential by enforcingand observing quarantine properly.

10. Use of pre-emergence herbicides. Herbicides which are used before the emergence ofweeds either before or after planting of crop, is a good preventive measure for preventing weedinfestation. Such herbicides either inhibit seed germination or kill young seedlings before theyget established.

B. Curative methods

1. Eradication of weeds

This method implies complete destruction of weeds. Weed eradication is achieved by killingexisting plants and destroying the viability of all organs of multiplication. This may be desirableand economical only when the weed is extremely noxious and persistent and makes the cultivation

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difficult or precludes bringing new area under cultivation. Eradication is not possible in oneseason or year as some weed seeds may have viability for as long as 50 years.

The underground parts can be destroyed by tillage or with soil sterilants. A soil sterilant,however, renders the soil incapable to support plant growth for several years.

When weeds are widespread and not feasible to eliminate, control measure would be morepracticable and should be given preference.

2. Control of weeds

Weed control refers to minimizing the infestation of weed so that the crop can be cultivatedsuccessfully. The various methods of controlling weeds are as under:

(a) Mechanical/Physical method

In this method, weed control is done using tillage, hoeing, hand weeding, digging, cheering,mowing, burning, flooding, mulching etc.

(i) Tillage: It removes the weed from the soil. It causes injury to root and pruning to shootof weed. The weeds in tilled field lose their regenerative capacity. Weeds are also get buried atthe time of tillage. The effectivity of tillage in controlling weed depends upon a number offactors. A field infested with deep rooted perennial grasses like thatchgrass(Imperata cylindrica),motha (Cyperus rotundus), quackgrass (Agropyron repens) having sufficient food reserve in theirunderground rhizomes and tubers, needs more cultivation with deeper ploughing than a newlyinfested field with annuals.

(i) Hoeing : Itis widely used weeding tool for centuries. Hoe is quite effective in controllingweed in row crop. It is very useful for annual and biennial weeds. In case of perennials, it destroysthe aerial growth. The underground growth is not much affected.

(ii) Hand weeding : It is done by pulling out weeds from the field. Pulling out is done withthe help of khurpi. Hand weeding is effective against annuals and biennials. The perennial weedsalong with underground portion are not pulled out completely and hence they regenerate in thefield. In fields which cannot be sprayed with weed controlling chemicals, can be made weed freeusing hand weeding.

(iii) Digging : Itis practised especially for the removal of shrubby and stubby woodyperennials. Prosopis juliflora (Kikar), Calotropis gigantia (Aak or Madar), Zizyphus nummularia and Z.rotundifolia (Jharber) etc. which grow in horticultural crops in arid regions are removed by diggingpit. This is ofcourse, costly and time consuming but very useful technique for the removal ofvery hard perennial woody weeds.

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(iv) Cheering : Itis done using cheer hoe similar to a spade with long handle. It cuts andscraps the above-ground weed growth. As the underground part of the weed is left undamaged,cheering is not useful in perennial crops which are regenerated by roots, tubers, rhizome etc.Cheering is widely used in India in plantation crops, particularly in tea.

(v) Mowing : Itis practised to keep the growth of weed under check especially in lawn. Theprocess of mowing is achieved by mower machine and hand blade havinglong cutting edge ofabout 1 metre. This method is successful only in case of short weeds growing close to the ground.

(vi) Burning : Itis very powerful technique of weed control in uncultivated field. It destroysaerial portion of the weed directly through flame of the fire and underground portion throughthe heat effect.

(vii) Mulching : It is getting popularity in controlling weed in a variety of horticulturalcrops. It excludes light from photosynthetic portion and. thus, inhibits the top growth of weeds.Mulching is very effective against annual crops. The mulches of straw, saw dust, paddy husk,paper, plastic etc. are common in use. The mulches should be about 10 to 15 cm thick for betterefficacy.

Materials such as black polyethylene have been used for weed control in a range of crops.Plastic mulches have been developed that filter out photo synthetically active radiation, but letthrough infrared light to warm the soil. These infrared transmitting mulches have been shown tobe effective to control weeds

(b) Cultural methods

In this method, attempt is made to control weed by practising agronomic practices. Cropand other practices done to grow the crop are modified in a manner so as to have minimumgrowth of weeds. The following cultural methods are practised to control weeds:

(i) Selection of crop

Selection of crop should be such that it may grow fast leaving weed behind.

The crop should absorb nutrients from lower as well as upper stratum of soil.

It should have less requirement of nutrients.

Water requirement should be minimum.

The crop duration should be less.

The crop should have dense canopy so that it may smother weed.

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(ii) Crop rotation : Crop rotation involves alternating different crops in a systematic sequenceon the same land. It is an important strategy for developing a sound long term weed controlprogram. Weeds tend to thrive with crops of similar growth requirements as their own andcultural practices designed to contribute to the crop may also benefit the growth anddevelopment of weeds. Monoculture, that is growing the same crop in the same field yearafter year, results in a build-up of weed species that are adapted to the growing conditions ofthe crop. When diverse crops are used in a rotation, weed germination and growth cycles aredisrupted by variations in cultural practices associated with each crop (tillage, planting dates,crop competition, etc).

Within a rotation, crop choice will determine both the current and the potential future weedproblems that a grower will face. Traditionally, potato (Solanum tuberosum L.) was included inthe rotation to reduce weed problems before a less competitive crop was grown. Crop choice iscomplicated further by the need to consider soil fertility levels within the cropping sequenceand to include fertility building periods in the rotation. Variations in crop and weed responsesto soil nutrient levels can also play an important part in weed management. The inclusion of afallow period in the rotation is known to reduce perennial weeds. It is best to alternate legumeswith grasses, spring planted crops with fall planted crops, row crops with close planted cropsand heavy feeders with light feeders.

(iii) Use of compost or manure : Decomposition of compost or manure starts after addition in thesoil. While decomposition, organic acids like uric acid is produced. Such produce prevents thegrowth of weed.

(iv) Allowing the land to fallow : In the fallow land the weed is deprived from moisture andnutrients. In the absence of moisture these weeds fail to grow. Now-a-days, with intensivecultivation especially in vegetables, it becomes very hard to leave the field fallow. Continuouscropping favours the growth of weed.

(v) Water management

Effective water management is a key to control weeds in horticultural crops. There are anumber of ways that careful irrigation management can help you reduce weed pressure on yourcrops:

Pre-germination of weeds : In pre-germination irrigation or rainfall germinates weed seedsjust before the cash crop is planted. The newly germinated weeds can be killed by light cultivationor flaming. Pre-germination should occur as close a possible to the date of planting to ensurethat changes in weather conditions do not have an opportunity to change the spectrum of weeds(cool vs. warm season) in the field.

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Planting to moisture is similar to pre-germination irrigation. After weeds are killed bycultivation, the top 2 to 3 inches of soil are allowed to dry and form dust mulch. At planting, thedust mulch is pushed away and large-seeded vegetables such as corn or beans can be plantedinto the zone of soil moisture. These seeds can germinate, grow, and provide partial shading ofthe soil surface without supplemental irrigations that would otherwise provide for an earlyflush of weeds.

Drip irrigation can provide moisture to the crop and minimize the amount of moisture thatis available to weeds closer to the surface. If properly managed, this technique can providesignificant weed control during dry period.

(vi) Sowing time : Later sown crop grows slowly and resumes less growth due to limitedavailability of growth period. Such types of growth allow the weed to grow vigorously leavingsufficient space and light for weed.

(vii) Orientation of sowing/transplanting : Sowing or transplanting should be done in such amanner that there may be maximum shade in the field. In shade, weeds fail to grow for want ofphotosynthesis.

(c) Chemical methods

In this method, chemicals are used for weedcontrol. The chemicals employed for weed control arecommonly referred to as weedicides or herbicides.Chemical weed control functions on the basis of thefact that certain chemicals are capable of killing weedswithout any significant injury to the crops.

A large number ofherbicides are now availablecommercially to tackle variousweed problems. A herbicidemay be selective or non-selective. A selective herbicidekills a particular type of weed orplant. For example, 2,4-D(selectively toxic to broadleafweeds). A non-selectiveherbicide (for example, Paraquat,Glyphosate) kills the whole

The discovery of 2, 4-D in the early1940’s has revolutionized the chemicalmethod of weed control. Marth andMitchell of U.S.A. in 1944 were the firstworkers to introduce it as a herbicide.

Herbicides applied anytime before the weed seedlingsemerge through the soi l surface are known aspre-emergence herbicides. For example, Simazine.

Herbicides applied after the crop seedlings (or weedseedlings) have emerged through the soil surface areknown as post-emergence herbicides. For example,2,4-DB, bromoxynil.

Herbicides that are applied before planting the crop -typically from several days to just before planting are knownas pre-plant herbicides. For example, EPTC, Glyphosate

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vegetation on which it is applied. Nonselective Herbicides (also known as Broad spectrum) areformulated to control both broadleaf and grass weeds. According to the type of action, herbicidesmay be classified as contact or translocated. The contact herbicide kills the plant parts where itcomes in contact (for example, Simazine), whereas the translocated (Systemic) herbicide goesinto the plant system and affects the whole plant (for example, Glyphosate). Use contact herbicideson annual weeds while systemic herbicides are more effective on perennial weeds than contactherbicides

The chemical weed control offers following advantages :

In crop rows, where harrowing or cultivation is impossible, herbicides can be easilyapplied to control weeds.

Herbicides give quick response in terms of checking the growth of weed and by thattime crop gets an escape and grow.

Hand weeding injures the root system of crop also and thus damages the crop.

Herbicides reduce the need of preplanting tillage. In case of minimum tillage,herbicides are very much successful.

The use of herbicides reduces the requirement of manual labour.

Control measures of weeds infesting fruit, vegetable and flower crops are given in table below:

Crop Recommended herbicide Dose (kg/ha)Mango Diuron or 2.25

Atrazine or 4.00Oxyfluorfen 4.00Paraquat 12.00Glyphosate 6.00

Banana Diuron or 2.25Simazine or 4.00Oxyfluorfen 4.00Paraquat or 12.00Glyphosate 6.00

Apple Atrazine or 5.00Simazine or 5.00Diuron 5.00

Paraquat 3.00

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Crop Recommended herbicide Dose (kg/ha)

Tomato Alachlor 3.00

Fluchloralin 3.00

Brinjal Fluchloralin 1.50

Onion Fluchloralin 2.00

Potato Metribuzin 1.00

Rose Diuron or 1.20

Oxyfluorfen or 1.00

Atrazine 3.00

Gladiolus Fluchloralin 2.00

(d) Biological methods

Reduction in infestation of weeds by direct or indirect actions of biological entities such asplants, parasites, predators and pathogens is covered under these methods.

(i) Plants as bio-agents of weed control : The differential growth habits, adaptiveness andcompetitiveness of the plant over weed, forms the basis of weed control by growing a particularcrop. Crops which grow vigorously have an advantage over slow growing ones which are sensitiveto weed. These competitive crops, also known as smothering crops, are very effective in weedcontrol. Growing of corn and ginger either alone or in combination, has smothering effect on thegrowth of weed. They grow more rapidly and fill inter-row space with their canopy faster thanthe weed. This gives smothering effect on the weed growth.

(ii) Parasites, predators and pathogens : In this method, the natural enemies of plants likeinsects and disease causing organisms are used. Insects kill the weed by exhausting the plantfood reserves and through destruction of photosynthetic parts.

Of the wide range of enemies, insects have been proved effective. Parasites like viruses,higher plants and fungi that develop only on live plants are also potent agents of weed control.

Lantana camera weed has been controlled successfully by the larvae of Crocidosema lantana-the totricid moth, which bores into flower-stem; Agromyza lantanae, the seed fly which eats flowerand fruit and Thecla echion which destroys flower. Cuscuta spp. (dodder) which grows on old fruitplants is controlled successfully by insect Melanagromyza cuscutae and Smicronyx cuscutae. Nutgrassor Motha (Cyperus rotundus), grows in almost all horticultural crops is controlled by insect Bactravermosana.

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The larvae of insect Diacrisia obliqua feed voraciously on Parthenium hysterophorus and destroysthe whole plant.

Pathogenic organisms damage the host plants through enzymatic degradation of cellconstituents, production of toxins, disturbance of hormone system, obstruction in translocationof food and minerals and malfunctioning of physiological processes. As a result plants die.

The fungi Alternaria macrospora and Puccinia heterospora control anode (Anoda cristata), a weedof malvaceae family. The fungi cause significant reduction in plant height, seed pod per plant,seed per pod and seed per plant. Fungus Cercospora roclmanii is effective against water hyacinth(Eichhornia crassipes) a problematic aquatic weed for waternut or singhara and lotus.

ACTIVITY/EXERCISE

1. Know the weeds growing on the farms in your locality and prepare a herbarium bycollecting samples of different weeds of your area.

2. Summarize the impact of common weeds growing in orchard, vegetable farm andwastelands.

3. Identify possible and potential approaches to practical weed management inpredominant horticultural crops of your area.

CHECK YOUR PROGRESS

1) Define weed. What are the characteristics of weeds?

2) What is critical period of weed control? List five commonly found weeds inhorticultural crops.

3) Differentiate between the followings:

a. Annual and biennial weeds

b. Common and noxious weeds

c. Selective and non-selective herbicides

d. Contact and Tran located herbicides

e. Monocot and dicot weeds

4) Write the various methods of weed control and discuss in brief the chemical methodof weed control in horticultural crops.

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5) Write short notes on the following

a. Tillage

b. Crop Rotation

c. Biological method of weed control

d. Harmful effects of weeds

e. Water management to control weeds in horticultural crops.

FILL IN THE BLANKS

1. Weeds are ……………. and ……………………..to their control and eradication.

2. The weeds which complete their life cycle within 3 or more than 3 years are knownas………………………..

3. Weeds compete with crop plants for…………., ……………… and ………………...

4. A …………………..herbicide kills a particular type of weed or plant.

5. A herbicide which goes into the plant system and affects the whole plant referred toas…………………………..


Chadha, K.L. 2001. Handbook of Horticulture. Indian Council of Agricultural Research. NewDelhi.

Chattopadhyay, T.K. 1999. A Text Book of Pomology. Vol. I-IV. Kalyani Publishers, Ludhiana.

Kunte, Y.N., Kawthalkar, M.P.andYawalkar, K.S. 2005. Principles of Horticulture and FruitGrowing. Agri-Horticultural Publishing House, Nagpur.


http://agritech.tnau.ac.in/org_farm/orgfarm_weed%20mgt.html

http://www.carolinafarmstewards.org/


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Major Pest and Disease Management inHorticultural Crops

OBJECTIVESAfter studying this unit the students will be able to:

• Explain the principle of pest management in horticultural crops.

• Explain the importance of various approaches in managing disease and pest incidence.

• Understand the importance of integrated approach of disease/pest management.

INTRODUCTION

Before we delve into the management of major pests and diseases of horticultural crops,we should be aware of what a pest is? The term "plant pest" means any living stage of organismssuch as non-human animal (rodent), fungi, bacteria, virus, nematode, any infectious agent(phytoplasma) etc. which can directly or indirectly injure, cause damage to, or cause disease inany plant or plant product. Plant diseases and pests have caused severe losses to horticulturalproduction in several ways. There are several pests and diseases, which cause small lossesannually throughout the world; however, collectively constitute sizable losses to growers; besides,reducing the aesthetic values of landscape plants and home gardens.

Management of major diseases and pests

Diseases and pests can damage horticultural crops from the time seeds/saplings are planteduntil after the crops are harvested, and gardeners/growers who fail to follow good growingpractices, which minimize damage from diseases and pests in their gardens/orchard may endup incurring significant losses. The goal of plant disease and pests management is to reduce theeconomic and aesthetic losses caused by plant diseases and pests.

Many strategies used in disease and pests management can be grouped under two verybroad principles of action, prevention and treatment or cure. The first principle (prevention)includes management tactics applied before infection/ infestation (i.e., the plant is protectedfrom disease/pests), the second principle (therapy or curative action) functions with any measureapplied after the plant is infected/infested (i.e., the plant is treated for the disease/pest attack).An example of the first principle is enforcement of quarantines to prevent introduction of adisease/pest agent into a region where it does not occur. For instance Ooty (T.N.) has quarantinemeasures in operation for golden nematode of potato. Similarly, the Ladakh region of J&K had

CHAPTER 9CHAPTER 9

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regulations for quarantine of codling moth of apricot. This implies that potato or apricot fromthese areas cannot be taken to other areas so as to check the spread of these pests from such areasto other parts of the country.

The second principle is illustrated by heat or chemical treatment of vegetative materialsuch as bulbs, corms, and woody cuttings to eliminate fungi, bacteria, nematodes or viruses,which are established within the plant material. Chemotherapy is the application of chemicals toan infested or diseased plant that stops (i.e., eradicates) the infection/infestation. For example,for elimination of grape fan leaf virus from grapes, chemical compound 'virazole' is employed.Likewise, for elimination of apple mosaic virus from shoot tip, plants are grown at 38 0C for 20or more days.

There are four general pest management principles viz., exclusion, eradication, protectionand resistance.

Exclusion

This principle is defined as any measure that prevents the introduction of a disease-causingagent (pathogen) or pests into a region, farm, or planting. The basic strategy assumes that mostpests can travel only short distances without the aid of some other agent such as humans orother vector, and that natural barriers like oceans, deserts, and mountains create obstacles totheir natural spread. In many cases pest are moved with their host plants or even on non-hostmaterial such as soil, packing material or shipping containers.

Exclusion may be accomplished by something as simple as cleaning farming equipment toremove contaminated debris and soil that can harbor pathogens/insect-pests such as Verticillium,nematodes or other soil-borne organisms and prevent their introduction into non-infested fields.

Eradication

This principle emphasises at eliminating a pathogen after it is introduced into an area butbefore it has become well established or widely spread. It can be applied to individual plants,seed lots, fields or regions but generally is not effective over large geographic areas. Two largeattempts at pathogen eradication, in the history of pest eradication, in the United States were thegolden nematode (Globodera rostochiensis) and the citrus canker (caused by Xanthomonas axonopodispv. citri and pv. aurantifolii) programs.

Eradication can also be on a more modest scale such as the removal of apple or pear branchesinfected by the fire blight bacterium (Erwinia amylovora) or pruning to remove cankers (causedby Coneothecium chomatosporus) on apples. Or, it can be the sorting and removal of diseased

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flower bulbs, corms or rhizomes. Hot water treatment of gladiolus corm 50 oC for 30 minutesbefore planting is followed to eliminate fungi.

Similarly, for export of fruits such as papaya, mango, mangosteen, and litchi to Japan forconsumption purposes the fruit is checked for quarantine pests such as fruit fly, as per PlantQuarantine Law of Japan. As per this law, any fruit that has undergone the process of "vaporheat treatment" (VHT) is eligible for import in Japan, as this process sterilises the pests withoutthe use of chemicals in an environmental friendly way. VHT is a non-chemical process of pestmanagement and control, which utilizes heat and humidity to control and fully eliminate pestgrowth.

Eradication may also be accomplished by destroying weeds, which are reservoirs of variousinsects, pathogens or their vectors. Elimination of potato cull piles is an effective method oferadicating overwintering inoculum of the late blight pathogen. Similarly, destruction of Tinosporaweed, an alternative host of fruit sucking moth, is recommended to contain the pest.

Soil fumigation has been a widely used eradication strategy. This technology involvesintroducing gas-forming chemicals such as carbon disulfide, methyl bromide, or chloropicrininto soil to kill target pathogens. However, undesirable side effects such as killing beneficialorganisms, contamination of groundwater, and toxicity of these chemicals may also occur. Volatilefumigants like methyl bromide are incorporated into soil and covered with a plastic film. Likewise,formaldehyde is also mixed in soil to disinfect it from pathogens.

Crop rotation is a frequently used strategy to reduce the quantity of a pathogen, usuallysoil-borne organisms, in a cropping area.

Burning is another effective means of eradicating pathogens e.g. flaming potato stems priorto harvest may prevent tuber infection by the late blight pathogen. However, burning agriculturalfields is controversial because the smoke creates human health and safety and environmentalconcerns.

Protection

This principle depends on establishing a barrier between the pathogen and the host plantor the susceptible part of the host plant. It is usually thought of as a chemical barrier, e.g., afungicide (chemicals used to kill fungi; cide=kill, which has been derived from Latin caedere i.e.to kill), bactericide (chemical for killing bacteria), insecticide (chemical for killing insects) ornematicide (chemical for killing nematodes), but it can also be a physical, spatial, or temporalbarrier. For example, bananas are covered with plastic sleeves as soon as the fruit are set) toprotect the fruit from various pests including fruit decay fungi. Similarly, bagging of pomegranatefruits with butter paper bag is recommended against anar butterfly.

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Protection often involves some cultural practice, which modifies the environment, such astillage to bury pest-infested plant residues, drainage, irrigation, or altering soil pH; besides,rotation to non-susceptible crops, selecting pathogen-free planting stocks, orientation of plantingsto improve exposure to sun and air currents, adequate nutrition, proper cultivation to improveroot growth and avoid plant injury, and sanitation procedures to eliminate sources of inoculum.It may also involve changing date or depth of seeding, plant spacing, pruning and thinning, orother practices, which allow plants to escape infection/infestation or reduce severity of incidence.Raising planting beds to assure good soil water drainage is an example of cultural managementof plant diseases such as root and stem rots. A range of fungicides, bactericides, insecticides etc.are available in the market for the management of pest incidence.

Biological control (also known as bio-control) involves the use of one living organism tocontrol another, and this management technology has received much attention in recent times.The examples of biological control in the management of insect-pests are use of Trichogrammachilonis against fruit borer in pomegranate; Chrysoperla against aphid, thrips and mites; andbaculoviruses against Helicoverpa and Cydia pomonella. Similarly, biological control of pathogenErwinia carotovora by several plant-growth promoting organisms like Pseudomonas fluorescence isa usual practice. Another instance is management of soil borne pathogens e.g. Actinomycetes(Streptomyces lydicus) reduced root and seed rot severity in peas and resulted in significantlyhigher final emergence and significantly lower final disease in spinach challenged by Pythiumand Fusarium (soil-borne fungi).

Resistance

Use of disease or pest -resistant plants is the ideal method to manage plant diseases andpests problems. Resistant plants are usually derived by standard breeding procedures of selectionand/or hybridization. For instance, pomegranate varieties Jyoti and BedanaBosec are resistantto the attack of fruit borer. Recently, resistant plants have been developed through the use ofgenetic engineering (e.g., resistance to the Papaya ringspot virus). Likewise, genes from thebacterium Bacillus thuringiensis have been inserted into plants to protect against insect attacks.Plants with these inserted genes are called genetically-modified organisms (GMOs).

Integrated disease management

Integrated pest management (IPM) is a broad based approach, which integrates a range ofpractices for economic control of pests. In most cases IPM consists of timely application of acombination of strategies. These may include site selection and preparation, utilizing resistantcultivars, altering planting practices, modifying the environment by drainage, irrigation, pruning,thinning, shading, etc., and applying pesticides, as per requirement. For example, IPM for mango

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hopper involves keeping the orchards clean, avoiding overcrowding of trees and water loggingto keep the pest at bay and three applications of carbaryl 0.1 % or phosalone 0.05 % at fortnightlyinterval, or, two sprays of phosphomidon or monocrotophos @ 0.03% at 13 to 18 days interval atflowering and 2 - 3 sprays in June - July. Similarly, IPM of tomato fruit borer (Helicoverpa armigera)involves planting marigold as trap crop, sprays of baculovirus, Ha NPV @ 250 LE /ha, mechanicalcollection and destruction of bored fruit at periodic intervals (3-4 times), chemical spray ofIndoxacarb 14.5 SC @ 0.5 ml/l or Thiodicarb 75 WP @ 1g/l. The integrated approach for themanagement of Panama wilt of banana caused by Fusarium oxysporum f. sp. Cubense is controlledby uprooting and burning of affected plants, use of disease-free planting material and resistant/tolerant cultivar such as 'Gold Finger' and 'Mutiara', crop rotation with paddy followed by bananafor 3-5 years once or twice, use of quick lime near the base of the plant and soaking withwater and avoiding sunflower or sugarcane in crop rotation, dipping of suckers inCarbendazim (10g/10 litres of water) are recommended. Application of bioagents, such as,Trichoderma viride or Pseudomonas fluorescence in the soil has also been effective in containing thisdisease.

ACTIVITY

1. Visit orchards/vegetable farm/ gardens of your area and find out the major diseasesand pests of important horticultural crops.

2. Try to collect information on prevalent management practices being followed in yourarea in different horticultural crops for the control of pests.

3. Visit a Biocontrol Laboratory of AgriculturalUniversity or Research Institution andsee how biocontrol agent, Trichogramma/Trichodermais being multiplied and storedunder laboratory conditions.

CHECK YOUR PROGRESS

1) What do you understand by term 'pest'? Cite some examples of pests in horticulturalcrops.

2) Enlist some important biological agents.

3) Differentiate between eradication and exclusion for pest management.

4) What does VHT means? How it helps in killing pests of fruits?

5) Discuss the effects of shoot and root pruning on vegetative growth and flowering of afruit plant.

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SUGGESTED READINGS

Arneson, P. A. 2001. Plant Disease Epidemiology.

Maloy, O.C. 1993. Plant Disease Control: Principles and Practice. Wiley, New York.

Maloy, O.C. and A. Baudoin. 2001. Disease Control Principles. Pages 330-332 in:

Enclyclopedia of Plant Pathology. O.C. Maloy and T.D. Murray, eds. Wiley, New York.

http://www.apsnet.org/edcenter/intropp/topics/Pages/PlantDiseaseManagement.aspx

http://agritech.tnau.ac.in/crop_protection/crop_prot.html

http://jnkvv.nic.in/IPM%20Project/ipm-home.html

www.anilrana13014.webbly.com

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